Engine build plan
 

My conversion has been on the road for a few years and about 10k miles. I'm pretty much at the point where I've shaken everything down and wouldn't mind upping the ante in the engine bay. The current engine is a novice freshening up. I've never had an engine apart before so I bought this used 5.0 and did rings and bearings and gaskets. It runs pretty strong but uses a fair bit of oil. I'd like to build a nice tight street engine.I don't have a budget in mind and won't mind spending some cash where needed, but I don't want to waste any money either. This is the plan in my head at the moment.
1) buy another used engine- tear down
2) send block in for hot tank and fluxing and possible boring and align hone
3) I would possibly have this shop build the shortblock, degree cam etc
4) with the shops help I would have to choose cam, and pistons, rods etc
5) I plan on buying a TMoss ported stock HO upper. (not the Cobra or GT40). I realise there are better flowing options but I really need this to stay under the stock hood.
6) not sure on what heads at this point...possibly AFR165? I'm using Martins headers, so I have to be careful to use something compatible.
7) Would be fantastic if all this could run nicely with the stock Foxbody EEC as it does now.

I'd love to be able to boast a 300+WHP build but that may be limited by my choice of intake. Am I on the right track? Also, I'm not totally adverse to assembling the shortblock myself since I have already done one. Degreeing the cam had me a little perplexed, but I've been watching some video's and I can probably handle that.
There is no rush on this...I'll probably do the build over the summer and swap it in next winter. Just planning and daydreaming for now.
Cheers.
Brad

New and built 5.0 engines are falling out of trees these days. They are professionally built, and ready to install. Generally speaking, they are available for purchase cheaper than you can do it yourself. It's not worth your time and effort to rebuild what you have. With a ready built engine on hand, the swap is almost a week end job. In some places, like Ford, the new engine also has a warranty.

Hi,

I agree with .bob.

Building it yourself is not cheaper, but is more rewarding.

Ok for a solid 300rwhp you will need...

331 or 347 cubes
Proper heads...afr 185 or trickflow 190 11r
Proper intake - trickflow fts r long runner
80-85mm throttle body
Cam with 220-224 deg of intake duration at 50 thou with 0.57-0.60 thou lift... Something like that from ed Curtis at FTI will do the job

Don't waste your time with the ho intake...its average...even after tom has worked his magic. It will choke the whole engine.

With the above you will likely hit 350-360rwhp and you can machine the intake, trim the hood and drop the subframe to make it fit under the hood...its really close but it can make it ��

If you are going to the trouble of getting the engine done, go the extra mile and you will not be disappointed.


Cheers

There are a large number of shops that sell these engines. Even Ford still sells them. Like everything else, there is a large variance in quality. You can buy a ready made package with standard parts. Or you can call Mike Forte and have him custom build whatever you want. All depends on how much you want to spend.

Blue Print Engines is becoming popular with the Cobra crowd, https://blueprintengines.com/collect...-crate-engines . And, of course, there's Keith Craft https://craftperformanceengines.com/Category/FSM302 f you want more displacement, look at Ford Strokers, http://fordstrokers.com/fordstrokers-long-blocks

I got a short block from DSS 24 years ago that has held up pretty well. DSS Racing Pistons - Stroker Kits, Racing Pistons, Main Girdle

Hi Brad,

Yes you are correct there is likely a variance in the quality of crate engines out there. But realistically speaking for the majority of people who run their engines on the street at anywhere between 1500-3000rpm on average (and have a 6000 rpm limit) don't really have high end requirements (boost and NOS excluded). Any of the Keith Craft, Ford Racing, Ford Strokers crate engines will work just fine and they all come with warranty and some with verified dyno sheets.

You could of course build it yourself as it is not difficult, but it does require care and attention to detail, especially when things are not plug and play (i.e. cam thrust or crank thrust end float clearance too tight, Cam is out when degreed, piston to valve clearances out of normal range, deck heights too low or high, lifter bores are burred and drag lifters etc etc.). There is a lot to do but if you take your time it can be done and in many cases you can get an as good or better outcome than the current crop of crate engines.

But building it yourself is a bit of a hassle and will take time plus you wont save much money by doing it on your own if that's your goal, but personal satisfaction and a rich learning experience of doing it yourself however can be priceless!

A better approach for you (if you are determined to get handy with the build) might be to get a built shortblock as that is where the tricky parts of the build will be (clearances, bearings etc.).

You can then build up the top end to make it whatever you want it to be. Me personally I would opt for a stroker shortblock, its just easier to make power with more cubes and you don't have to do all the time consuming and dirty piston, bearing and clearancing work.

If 300 RWHP is your goal, I can attest to the fact that a 5.0L can get to 300RWHP but a stroker setup makes it so much easier and will drive a lot better with the increased torque. Its just not quiet as smooth as the 5.0L from a vibration perspective, but its only very slight.

But whatever you do (5.0L or stroker), use aluminium heads (AFR 185 or TFS 190 11R) and a proper intake manifold (i.e. the Trickflow R long runner intake with 75mm TB opening for 5.0L or 90mm opening for stroker) and a custom billet steel camshaft with around 214-224 deg of intake duration @ 50 thou lift and 0.57-0.6 thou of lift. I am assuming that you will be street driving most of the time and in traffic a lot hence the milder cam spec recommendations. I would also recommend a custom cam as this is very important. It ensures that all variables of the car and your end goal requirements (i.e. smooth idle, power steering, power brakes, air con, wheel and tire diameter, gearing etc) are all taken into account. For the minor price difference it is definitely worth the effort. On top of that add a 75-90mm Throttle body (75mm for 5.0L, 80-85mm for 331/347 up to 500hp and 90mm for over 500hp).

What you want is an induction tract from TB to intake valve that will flow 300cfm. The ford 5.0l factory setup is about 200-215cfm. This is where all the power is lost in the factory engine and gained by the aftermarket heads and intakes.

Also do NOT buy AFR heads and bolt on the HO manifold. If you are going to do that just keep the iron heads you have now as the AFR heads wont be able to flow any more than the point of smallest restriction (i.e the HO intake).

From my experiences I have used a TMOSS ported explorer intake on my 5.0L and on some of my older strokers. For a 5.0L the ported TMOSS manifolds are OK, not earth shattering but they are a definite improvement (intake tract flow goes from 210cfm to about 240cfm) with a decent head like an AFR 165 or TFS 170 11R you are in a decent position. However it is a far better option to just get a solid flowing manifold (and head) from the onset that can deliver the flow needed to make the required horsepower.

I prefer to have as much flow as I can in my inlet system so that I can make my cam as small as possible to meet my goals. The Off The Shelf cams mostly assume that the factory intake and heads are to be used, hence they have lower valve lifts (due to assuming weaker than required springs and losing engine torque in the process) and longer durations than required to get the result (thereby degrading idle in the process) . Hence my preference for custom cams these days..been down the OTS road many times...and was never fully satisfied for the effort involved.

As an example of how dramatic the end result differs when you do things in a not so good way..
I had the following many years ago..

331 stroker, TFS 170 heads, CompCams XE264 (214@50 with 0.55 thou lift) , TMOSS Explorer ported intake manifold and 70mm throttle body - Result was 283 RWHP (underwhelming for me considering the expense and trouble). I went looking for answers to my HP shortfall and found out that my intake flow was killing the car's power, the car's power curve was pretty much flatlined after about 4900 rpm. This was mostly the intake manifold causing this drop off.

After spending a lot of time with Dynomation (engine simulation software) and modelling my old setup and verified its deficiencies I went about modelling a new one. I arrived at a new more powerful configuration for that same engine but I needed to make a few changes;

I changed the following:

Changed Heads to TFS 190 11R - (Head flow went from 250cfm to 300cfm)
Changed TMOSS Explorer Intake to TFS R 75mm long runner - (Intake flow went from about 240 cfm to 300cfm)
Changed Comp XE264 Cam to custom Ed Curtis Cam 215@ 50 0.6 thou lift (very similar duration to old cam but with slightly more lift..)
Changed Factory 70mm Throttle Body to 75mm Accufab (TB flow increased from 680cfm to 924cfm)

From only the above changes the power moved from 283 RWHP to 333 RWHP (an 18% improvement). The difference in adding 20 odd percent in airflow is closely correlated to the same level of power increase.

This is an additional 50 RWHP (or about 60 FWHP) delivered with NO cubic inch increase , NO increase in engine MAX RPM, almost NO additional camshaft duration and NO loss of bottom end torque.

This was very valuable lesson for me in understanding just how dramatic the effects of a strong flowing intake system are to ensuring that the engine delivers its performance potential.

I could have done it properly from the beginning but I learnt the hard way...but you can benefit from my experience :)

Whether you go Crate long block, Crate shortblock or build it yourself, you have some time to plan and think about it before pulling the trigger. Whichever way you go for the build just make sure you keep us posted so we can all collectively give you as much of our experiences as possible to ensure that you can then make an informed choice for your "new" Miata.

Keep us posted in your dreaming phase as that is where all the right and wrong decisions are made :)

Hope that helps you..sorry about the lengthy rambling...!!

Cheers

Hi Brad,

If the EECiV is custom tuned for the application (assuming the injectors are upgraded, along with maf and fuel pump) I cant see why not. Although the EECiV isn't super sophisticated it should run the car OK if custom tuned properly.

I run a custom tuned EECV on mine. It was tuned using an SCT tuner.

Cheers

Hi Brad,

Apologies for my assumptions in my posts being slightly askew...I just realised that you are using the HO manifold and NOT the Explorer style manifold (hence my quoted figure of 240cfm for the TMOSS ported Explorer).

Yes for the HO manifold the TMOSS ported version will flow around 200-210 cfm.

Yes using the AFR or TFS 165 or 170 heads respectively will be perfect. But you will be leaving HP on the table with that intake. The Aluminium heads (either AFR or TFS) are quite a bit lighter and you will notice the difference (its about 70 pounds lighter across both heads).

If you plan on sticking with 5.0L in capacity and add a 70-75mm TB, a mild cam (214-218 deg intake duration @ 50 thou lift) and use 24-36 lb injectors @ 43psi. You will probably end up at around 230 rwhp.

Brad: Could you please measure the height of your manifold from the machined underside of the end rails to the top of the upper intake. I am curious to see what dimensions your installed intake has.

If it would be possible, you could even get a TMOSS ported explorer style manifold (about 240cfm flow) which will get a better result from the AFR 165 or TFS 170 heads. Say around 250-270 rwhp with cam and TB.

One of my older 5.0L combos was this:

TFS 170 heads
70mm TB
TMOSS ported explorer
214@50 cam with 0.5 lift
4-2-1 headers

This combination made 258 rwhp and the cam was very very mild. With a better cam (i.e. XE270) it was likely good for 270 rwhp.


A 331 Stroker with AFR 165/TFS 170 heads, 70-75mm TB, a mild cam and the ported TMOSS explorer intake will get you around 285 rwhp.

Any more HP than that and you will need a much better intake and or heads to get the numbers...

Also just for the record, you could simply perform a very mild "power bulge" enlargement on the hood as I had done to get you the precious 1/4 inch needed to clear any intake. That would not be very expensive either. Hardly anyone notices mine has been modified (see pics from my build thread)...but 1/4 inch is all the difference in the world for these cars :) lol.

In essence at best a 5.0L with a ported intake will get you 260-270 rwhp...a stroker around 285 rwhp (but much more torque). That is with both combinations being very very streetable as daily drivers.

Let me know your thoughts....

Cheers

Yes it is a straight bolt on

You may have to adjust some vacuum lines, otherwise pretty much straight forward. I have the Explorer setup on mine, and had the lower milled 1/4" for clearance. I run Ford Racing valve covers, so that added a few other issues I had to address. Stock valve covers should be fine with the milled lower.

Explorer has 70mm opening, good to go there. I have a few EGR spacers on mine as I had to push the TB out to the side more to clear the valve cover with the throttle linkage (ford racing covers and milled lower). I went with stock 93 Cobra MAF and ECU for 24 lb injectors to up my fuel game. I have TFS Stg 2 cam with TFS heads and 1.6 rockers. I had to get a silicone elbow and trim to fit with small cone filter for MAF, but it fits. Pics in my build thread.

Yes, I concur, + 1 from me.

The 70mm TB opening for the Explorer intake is there (actually I think the opening is like 68mm...so a bit of work with a die grinder will help...or at least it was on mine). The stock 93 Cobra MAF and 24lb injectors will give decent control until about 275 RWHP. After that a move up to a Ford lightning 90mm MAF will be needed for proper mapping control (wiring and plug is the same). The Cobra MAF will flood at 275RWHP (i.e. voltage signal to ECU is pegged at 5V) and after that the ECU gets no more understanding of increased airflow post that point. Also the 24lb injectors will be at 90-95% duty at 275 RWHP. I would step up the injectors (32 lb or more...I run 39lb Ford Racing) and the MAF (90mm Ford Lightning) if the target RWHP is over 275 RWHP. Its just safer and easier to tune properly with a bigger MAF and injector setup.

Cheers

Well, a FRPP Cobra upper and lower just came up for sale on a nearby Mustang club classifieds. I had first crack at it and after seeing pics of what looks to be a near mint pair, I e-trans'd a deposit. Will probably go pick it up sometime next week. Maybe I'll get lucky and TMoss will have already had at it.)
I'll have to make a spreadsheet of all the parts I need to gather. Cobra TB and MAF next I guess.

You need the matching MAF and 24 lb injectors, as it is programmed for those components. Otherwise a direct bolt in. Swapping to Cobra ECU and MAF solved all my bad running issues when I was running the A9L with Pro M MAF for 24s and 24 injectors, MAF was sending lean signal to ECU, so it was running pig rich to compensate. Runs great now on the Cobra stuff. Needs to be from a 93 Cobra.

Great work on securing the intake. You won't be disappointed.

Also on the tune, I would strongly advise to have the car custom tuned once it is running. It will make a huge difference in drivability. Easily done by a good tune shop.

cheers

Yeah, that seems steep. TFS are great heads. I think I picked mine up for $600 for the pair, used. They were low mileage and mint, no problems.

Yes that is steep. I would buy them new. For the few hundred saving its not worth the hassle. The TFS 170 11r heads give you slightly better gas flow behavior due to the rotated valve position. Not much in it when compared to AFR ..but it helps. Also helps slightly with piston to valve clearance with higher lift cams.

Just get them new....that way all springs and seals and surfaces will be perfect. Just make sure you pour lots of oil over the valves before sealing with the valve cover. I even use a syringe to make sure the valve stem seals are properly soaked before I seal them up.

You will have a good experience with new heads, used heads can be warped, have a bad seal etc.

Cheers

Well, all the reading I've been doing over the last couple days leads me to locking in the AFR 165 58cc heads.
https://www.jegs.com/i/AFR-Airflow-R.../1399/10002/-1
They are ready to bolt on right out of the box. If I buy used heads I'd need them checked over and who knows what expense to make them as new.
With a ported Cobra lower and the heads chosen I think I have all the info I need to contact Ed Curtis about a cam, though it looks like the Comp Cam XE's are a good off the shelf choice.

Excellent. That sounds like a much better plan than the one in Post 1 :)

Yes the new AFR 165 heads will be perfect and Ed's cam will give you a solid 20 hp over the XE cams, I have simulated the XE cams against Ed's cams with Dynomation for years and Ed wins every time and by a good margin. Just make sure you get a billet Steel cam from ED AND you double check that you have a steel gear distributor.

Looks like you are set Brad :) It will be good for around 340-350 FWHP.

Cheers

Hi Brad,

Your oil consumption if small could be from the following areas:

1) Excessive piston bore clearance
2) Rings (excessive end gap, installed upside down or gaps out of correct rotational alignment)
3) Bad valve stem seals
4) Bad cross hatch in bore

1) The Piston to bore clearance should be around 1 thou for cast piston and 2.2-3 thou for forged. Larger clearances will increase of oil slipping through. It will be slow though. In your case if you did not buy new pistons and or machine the block then this could be where your oil consumption is coming from.

2) Rings need to be installed with the right end gap as checked in the bore. For these engines the top ring should be around 18 thou and the lower ring around 20-22 thou. The ring MUST be installed with the pip or dot facing UP. This is easy to miss if you are rushing, working late at night or were never shown how. Even now I always triple check my work here. Same goes for the oil rings, the expander rail must be installed correctly so as not overlap the ends so the oil rings sitting correctly. The end gap alignment for all rings needs to be correct as well. The oil rings need to be aligned as follows with 12 o clock on the piston being the FRONT of the piston that points forward:

Bottom oil ring at 11 o clock
Expander at 2 o clock
Top oil ring at 7 o clock
Second compression ring at 9 o clock
Top compression ring at 3 o clock

3) Stem seals are a very common area for oil consumption, the seals allow oil to creep past at slow engine speeds like idle. If it smells oily at idle then chances are its these things. Sometimes if you don't lubricate them if new at assembly they burn up fast due to running dry for a little on first start up until the oil comes up (that's why we always need to pre prime an engine's oil pump and lubrication system prior to first start) . This makes them wear abnormally fast. The valve stem seals always come up a lot for oil consumption issues....if it smokes or smells at idle, but full power looks clean (i.e. not smoky) then it is probably the valve stem seals. The valve stem guides are also an area of oil seep, many people do not replace the guides when they rebuild the heads (mainly due to cost), this can lead to slow but steady oil consumption...again mainly at idle. Replacing the valve guides is costly and it is much better value to just buy new heads.

4) If you just do a re ring (i.e. no bore machining) then there is a chance that the rings don't fully seal 100%, due to the bore being too smooth with no cross hatch. A compression test will reveal this quickly though.

In your case all of the above need considerable effort to investigate and or rectify. My advice is that you will remove the top end, valve stem seal and guides issues with the new aluminium heads...and if you have time on your hands and or funds, a new shortblock (rebuild yours or buy new) will fix the others...you can then sell the existing engine to cover some of the costs. That way you will get the best result.

Do it once and well is my philosophy...especially in these cars where the packaging is tight and the effort to get to things is higher.

cheers,

I agree, one and done. A lot of time and cost to tear down and engine multiple times.

Well, my plan is underway.
I bought some cheap Flotek heads back in the spring, had them checked over and ready to go. Bought an Explorer intake manifold and sent to TMoss for porting. Also got a 65mm TB and EGR spacer and E cam.
I pulled the motor last week and dropped off to the machine shop on Monday. They’ll get back to me this week with what needs done. Took tranny to the guy who built it for a quick checkup, and brought all my pretty parts to the powdercoater.
I was surprised the amount of carbon on the tops of the pistons when I pulled the heads. I got good compression readings but obviously had a lot of blowby. Happy to finally get this done.
Another perk: I really lucked out finding this powdercoater. He does great work for very reasonable cost and is also a master fabricator. Anything to do with metal, he can do it.

Edited to add:
Machine shop called me this aft. They’re boring the block .30 and decking it. They’ll have it done next week sometime. I have a busy week and won’t be able to finish assembly till the following week. Not that there’s a rush....I won’t be able to get it back on the road till spring.

Sounds like it will be a fun setup.

it's the same MAF. juste the injector change

Engine Build
 

Hi Brad,

Great work getting it started!!. Things are looking good... :)

I would only suggest that you consider a better cam. There are likely much better options out there. I am not sure which Flotek heads you have but there is a bit more flow to be had when the lift goes over 0.5 in, you B3030 cam does not even lift 0.5in. If you have your heart set on the B303, then use 1.7 ratio rocker arms to get a bit more lift and therefore torque.

Also a 70mm TB would a better proposition too..but 65mm is OK.

Looking forward to you putting it all back together again and reporting back :)

cheers

Yes, that was a decision based purely on economics. I talked to Ed Curtis about a cam, and his price was decent...about the same as an off the shelf Comp Cam, but the springs on these heads will only support up to .550 lift. His upgraded spring package cost more than his cam. I got the E cam basically for free so it was an easy decision to do that for now, and save up for a custom cam and springs for next year. At least I know I’ll have a good bottom end to build on. The 65mm TB was a deal I couldn’t pass up. Though not optimum, it should still be a pretty well matched combo.
We start assembly tonight.

This has been a great thread!

I am rebuilding my 302 this winter and I've been collecting parts like gt40 heads I plan to Port and polish, a tunnel ram and 1 5/8 headers.

Matching flow rates makes total sense.

Where do you get the flow numbers for the intakes and heads, do you have your own flowmeter you use for measuring?

I'm curious how I would measure the improved flow after my port and polish.I know how I can do a single port with a vacuum and a mercury gauge, to measure relative improvement.

But I don't know how I would flow the whole head (or intake) and get an absolute number.

Thanks for all the super helpful replies engineer!

PS, my build is for a track car more than street car. So low rpm torque and grunt matter less than smooth high rpm operation and peak hp.

Hi Walkingspanish,

Firstly your questions answered…

1) I get my flow numbers from the internet :) I mainly use the manufacturers flow rates..but occasionally some head tuners and magazines online publish some great data, here is a slightly older article from Fordmuscle but it is still a great resource of info for small block ford head flow rates...

https://www.fordmuscle.com/archives/...eads/index.php

2) Measuring your port and polish improvement at home is not difficult as you can indeed make your own flow bench..its a bit tedious but can be done..see this article if you are keen to go down this road Flow Bench

3) This site is a real gem for flow rates on intakes and heads... http://www.abbottssuperflowport-poli...w-Numbers.html

Now if you wanted my input...for whatever its worth :)

1) if you want to make a more race orientated engine then you MUST get rid of the GT40 heads. They barely flow 200cfm in stock form. Secondly even after porting polishing etc you can only expect them to hit 220cfm...no way near enough o make any power for a racing style of engine.

2) Save yourself the head ache and hassle and save up for a set of AFR or TFS 185 or 190cc aluminium heads. They flow 300cfm out of the box...bolt on. Well worth the money. Its a massive difference and it will make you much more power. You need to have a min of 250 cfm intake flow to make any real horsepower.

3) You need a comparably high flowing intake to match up to the flow rate, Your tunnel ram may do it...I am unsure what brand or type it is. Just make sure it can flow 300cfm per runner too. Or again save up and look at an Edelbrock Victor Jr or super victor they flow close to 300 cfm. Some of the Performer range can get close to 250 cfm. Up to you how far you want to go...but needs to be as strong as the head flow in cfm.

4) Carburation look at Edelbrock AVS2 650 cfm (great carb, air valve secondary, jet changes without taking carb apart etc...its very tuneable if you know them and will make just as much power as anything else under 550 HP if properly tuned. If going above this power level you need something more specialised). I have used them for many many years (way back in the 80's Carter Days) and they are super great for driveability and throttle crispness. They will deliver more than enough grunt for your 302...and it will start every day :) But if you must go holley look for a Quick Fuel Technology Holley with 650 cfm

5) Cam...look at a billet steel custom cam. off the shelf cams are always a compromise. Its mildly more expensive but worth every cent as you get every last bit of power out of the engine. Shoot for 228-235 deg of duration @ 50 thou lift AND go for an overall valve lift that matches your head flow's potential..i.e. if your head flows 300 cfm at 0.6in then get the cam to lift that much too...most off the shelf cams stay under about 0.57 in lift...leaving power on the table. The 228-235 @ 50 cam will be driveable but will have a lumpy idle...but not bad enough where its a pest to drive. There are larger cams that can give more power....say around 245 deg of duration @ 50...but the driveability is not great...better to undercam slightly and have it be driveable, so you can use the car when not racing it.

6) keep compression around 10-10.5:1 - with cranking pressure around 185-195 psi
7) Invest in good rockers and valve springs to handle the lift (around 150-155 lbs on the valve seat...PAC dual spring setup )...if you get the AFR or TFS heads the springs are already done for you.
8) Good roller rockers...shaft design is better (more stable) that stud mount for high rpm (5000-7000 rpm) but costs a bit more...stud design is OK,..just get the thicker rocker studs option if you go studs.
9) Rear end Gearing will need to be about 3.7 - 4.1
10) Use a Tremec TKO 500 or 600 transmission..Tremec/Ford Racing T5z...may be OK for street but if racing it...it will be very marginal

Above should net you a solid 400hp at 6600-7000 rpm with a good mid range torque band...and be driveable on a sunday :)

Enjoy! :)

Thank you for the links! Super helpful!

2) For the GT40 heads, ouch! I thought with porting and polishing I would be able to bring them to 250 cfm range. I've managed to keep the whole build really cheap so far, so I think I can splurge for the heads.

3) I found an old Weiand Tunnel Ram, I believe it's a 1988 (https://www.summitracing.com/parts/wnd-1988), it only has the single carb upper intake though. I figured that was fine.

4) I am running a Holley 1850 right now. I figured that will probably get me going for now, but I'd prefer mechanical secondaries for track usage. I'll look at the Edelbrock!

5) Any recommendation for custom cam makers? How much am I looking at for a custom cam?

6) Is 10.5 the max I should go, or is that pretty much the max for pump gas?

7 + 8) Yeah roller rockers for sure. Any recommendations? I was going to get the thicker studs and cam stud girdles. Are shafts that much better?

9) Yeah, I need to decide on the wheel / tire sizes so I can finalize what gearing want to run.

10) I have a BW T5 I picked up fro $140, so that's what I'm going to initially use. I figured it would let me easily swap to the TKO500 in the future.

Do you think I'll be able to get 400 ish hp? I've been checking out dyno charts and I notice getting over 300 from a 302 seems to be a challenge! :)

Thanks so much for all of the help!

OK sweet..,my answers below...

2) Great...glad you are going for the head upgrade. You wont regret getting better heads...that is where all the power is.. :)
3) Tunnel ram should be OK...I will look at the flow figures if I can find any..
4) The Holley 1850 is OK. However mechanical secondaries will always give a better "feel". The Edelbrock AVS 2...is actually the best of both worlds...it has mechanical secondaries BUT they are fed by an adjustable air valve. Which means the air valve wil open when the engine air speed demand is high enough to allow the flap to open. It will bring a smoother transition from part throttle to fullpower….and its super tuneable too..as you can adjust the both the mechanical secondaries AND the air valve for precise secondary actuation. Also the Edelbrock AVS 2 has annular discharge boosters too for superior fuel atomisation. PLUS you can change the step up spring (power valve), metering rods (jetting) all without taking the carb apart.. try getting all of that functionality from your holley :)

5) Ed Curtis at Flow Tech Induction does the best custom cams for Fords. Cost is around $400 USD...worth every cent...just make sure you get a billet steel cam core. The Austempered cores are cheaper but they are NOT as robust as the steel cores. So chances of rounding the cam lobes is higher...been there done that...Billet Steel only now for me :)

6) 10.5 is about right for street/strip duties with an aluminium head and a mild to medium duration cam (220-230 deg @ 50). With iron heads the compression ratio value is less by about 0.75 points. So for example a 10.5:1 aluminium head engine can tolerate the same fuel as say a 9.75:1 iron head engine. If your cam gets larger with longer duration you can go higher on the compression with either heads. Aluminium heads give you a much better capability for increasing compression. Keep it between 10-10.5:1 on aluminium heads and 9.5-10:1 on iron heads with a 220-230 @ 50 deg cam. The Aluminium headed engine will run better though with everything else being equal due to increased compression...it will feel perkier on the throttle...less soggy.

7) Are Shaft rockers better ? Yes, by far if you are running constant high RPM in a racing engine...for short burst racing or the street then the studs are fine...with girdles even better. Check out the Jesel shaft rockers here Jesel Pro Series Rockers - SBF TFS TW11R - FlowTech Induction. For roller rockers I use the trickflow branded ones which are made by scorpion, but other brands are also very good i.e Yella Terra). Shafts are indeed better but they are double the price, if you are circuit racing for long periods of time or you need a bullet proof setup...then get shaft rockers..otherwise studs are OK.

8-10) The T5 wil be Ok for a while in a miata...but when it goes get a TKO..its a much stronger unit than the T5.

Yes it is not super easy to get 400hp from a 302 and have it be useable on the street, however if you provide a chunky custom cam (about 230+ deg of duration and 0.6 in lift), rev it to 6800-7000 rpm and have a great flowing 300cfm induction setup (heads and intake and carby) it will get there...or very very close to it.

As an example Trickflow rate their SBF top end package at 350 hp on a 302 with 250cfm of intake flow from the 170 11R head and the track heat manifold and a 220 @ 50 cam. So with an extra 20% of intake flow and more cam you will easily get the extra 50 hp you need to hit 400 hp...


OR you can go stroker...that is an extra 30-40 hp straight off the bat with the extra capacity...not to mention the torque..

I would take the stroker any day (331 is my choice) ....torque is soooo much better... :)

Enjoy...let me know if you need anything else.

Yeah, one question regarding strokers...

I want something that likes to rev, and I was concerned about the stroker kit adding too much vibration. Is that true?

Also, why 331 and not 347?

Another thing, is it worth reconditioning my block or should I make my life easier by starting with a DSS or even a short block and going from there?

​​​​​And when should I give up and buy an LS? :-)

​​​

OK...

1) strokers can add more vibration....however if the engine is balanced properly it will be negligible. This is most important, many shops think close enough for balance is OK. However strokers need to be balanced a little better than close enough o ensure that they are smooth running and rev nicely.

2) Your rev limit goals need to be realistic. The ford small block is not a rev monster. Most street based (i.e. not race dedicated) strokers stop giving power at around 6600-6800 rpm. There is little point pushing them past this for more power. I like to cap the rev limit to 6000-6250 when using a stock block and around 6600-6800 rpm with an aftermarket block. Engine speeds greater than say 7000 rpm will start to reduce the life of the engine. An engine with a rev limit of 6500 rpm will last a very long time if built properly, plus the extra 500 rpm will likely only yield a few HP more anyway...not worth stressing the engine for another say 10 hp.

3) Why a 331 ? Well for me the piston has a larger skirt than the 347 and as a result will be able to support it a lot better. The 347 piston is very short on the skirt so it rocks around a bit more. Secondly the piston ring intersects the gudgeon pin and I don't like that personally for a long life engine. It will also use more oil and can be smellly as well on the exhaust as it will burn a little more oil. Also the 331 requires no block clearancing which is handy. Plus the rod to stroke ratio is more favourable for the 331. However when using an aftermarket block to make a 347 things change. Pistons are larger but stroke is same as 331 at 3.25in, so rod to stroke ratio is the same AND the piston is the same skirt height as the 331. AND the oil ring situation is gone.

So if you have an aftermarket block then its 347 all the way with a 3.25 in stroke...

4) Up to you if you wan to use your block or not...HOWEVER if you are serious about racing the engine and giving it a hard time ALL the time, then I would strongly advise that you use an aftermarket block for the build. The stock block is ok for the odd burst of anger but sustained load under race conditions (i.e. circuit or long distance edurance racing) will push its limits. Plus its not much more these days for the aftermarket blocks. They are better in every respect...except 1. They are heavier by a fair few lbs.. :) I would buy a stroker short block with aftermarket block (Dart or Ford Performance)forged pistons ( I like Mahle) and forged crank (Scat is fine) again if you are really going to race it hard and go from there. DSS, CoastHigh, Fordstrokers and even ford performance (507hp 363!!) have good short and long blocks for you to pick from.

Cheers

Engine is finished, in the car and driving.
To recap, I have a '94 block that has been decked and bored .030 over. New pistons, polished stock crank, E303 cam, TMoss ported explorer lower, explorer upper, Flotek 180 heads, PRW roller tip 1.6 rockers, 65mm TB and functioning EGR spacer. Stock MAF 19 lb injectors. Stock EECIV FI system, 3G alt.
Good news is that my bubbling coolant issue I was having pre rebuild, is gone. Also, I have NO leaks whatsoever. I've been putting some break-in miles on it over the last couple days. Sounds like I may have to go back and redo my rocker adjustment, getting a bit of sewing machine type clatter. I've been pushing the RPM's up gradually. I have about 300 miles on it now and it seems to pull hard, but I have a few issues that I'm certain are electrical in nature. I have the dreaded low speed bucking and even at cruising speed when you let off the gas it feels like a harsh transition. Kinda like you're full on or full off the gas....no easy cruising in between. That translates to it being a handful in stop and go traffic.
I've done a TON of reading on this, as it was doing the same thing pre rebuild.
I have checked all the usual stuff:
Pulled codes- only the air pump delete codes come up, cylinder balance tests good
Vacuum leaks- none, pulling about -13- -14hg at idle but steady
TPS
all other sensors are new except MAF (but I get no codes)
Varied timing from 8* to 14*
Adjusted throttle stop ad nauseam

Unrelated, my T5 is making some strange clicking noises at speed. I'll see what the rebuilder thinks. Otherwise I am on track to have a pretty nice car if I can just get this damn bucking solved.
I suppose I'm going to need a tune.

Just added: just went out to start it again and it would stumble and stall. Could not get it to stay running until I unhooked and reconnected the battery.

https://cimg9.ibsrv.net/gimg/www.v8m...afd7bd1ae.jpeg
https://cimg4.ibsrv.net/gimg/www.v8m...86dffec2a.jpeg

You need a tune, I had the same thing with mine running trick flow stg 2 cam. Tuner was able to work it out for the most part, car was no fun before it was tuned.

Curious what that cost, and what issue(s) if any he wasn't able to tune out.
I'm almost considering going Megasquirt. Not sure if that would be over my head though.

It was $600 including cost of chip. The gas mileage is much better, pills much harder, and the surging is pretty much gone. He does street tuning, and the day he had the car it was raining, so I have to take it back in the spring when the weather clears for some WOT tuning. There is still a slight surge below 2,000 rpm, has to do with cam. He’s going to try to work on it a bit more. Also has to fix a cold start issue where it stalls first attempt when cold, is fine second attempt. I had a MS in this car when it had turbo 4, I hated it. This runs way better than I ever had that MS running. That’s just my opinion, I’m not a trained tuner. I had original MSPNP, felt it did not have enough tables to get a smooth tune.

Thanks. I appreciate the info. Ya, I'm apprehensive about the MS. Think I'll just look for a tuner around here.

Your engine compartment looks awesome! It could be a factory car that just rolled off the assembly line.

When you unhooked and reconnected the battery you wiped out the "learning" memory of the ECU and restored it to factory "default." The fact your car runs better on a default tune than after it has been "learning" based on sensor inputs under real world conditions suggests "bad info" is being fed to the ECU, resulting in A/F ratios/timing adjustments that are contrary to actual engine needs.

Double check that your wires to the left and right oxygen sensors are not switched. That could create the behavior you suggest.

If it isn't that look for something else giving the ECU errant info and causing it to adjust A/F in the wrong direction.

Looking great Brad, I am so happy you got it going! Hopefully you will get the tune sorted out and it will start behaving better. Keep us posted :)

Cheers