engineer

Hi All,


This is my first post..I am a long time observer on these forums but I just joined as a contributor today


I am after a definitive answer on the dimension for the intake manifold to hood clearance.


I want to use my favourite TFS R long runner intake on my yet to be built 331 Stroker that is going into an NB 2001 Series 2 Miata.


But I have noticed that the hood clearance could spoil my show....and I don't want to run a hood scoop.


I have measured the following intakes from the end rail surface to the top of the assembled upper intake.


I have the following dimensions:


1) Ford explorer style std intake (273.9mm or 10.78 in.)
2) TFS R (279.5mm or 11 in.)
3) TFS Street/Track Heat (259mm or 10.2 in.)
4) Edelbrock RPM II (279.5mm 11 in.)


So my question is what is the critical dimension between the block end rail intake surface to the hood to enable the intake to clear without a hood scoop???


And I understand that some people may have milled their upper or lower (or both) manifolds AND spaced the front subframe down to get the clearance.


I am happy to do any or all of these but it would be great if some kind person could provide the definitive answer on what is the dimension required to clear the hood as measured from the block end rail surface.


I look forward to everyones response..


Cheers
John

tbone heller

Those dimensions change from car to car depending on the location of the engine. Some try to mount it as far rearward as possible. Some have to add more spacers at the motor mounts to clear the steering rack. The rear of the transmission can be raised & lowered as well thus changing intake height.

engineer

I understand it varies from car to car...however I just want to get an idea of what dimensions (and there will be a variance) actually clear the hood. I just want to see if my TFS R intake will br int he zone to clear the hood or if I have to drop to a lower profile manifold such as the trickflow track heat which is 0.8 in lower.


Any dimension would be appreciated

MiataDoug

I just got my engine installed and I can shut my hood. I would be glad to take a measurement for you if it would help you. I am not sure what feature of the engine block you are talking about when you say "end rail"? I have martins spacers installed between the engine and the mounting plates. I have shimmed my K-member down. I cant remember how much. I would have to measure it. I have a telescoping magnet that I have used before to get the kind of measurement I think you want. I just put the magnet end on a flat iron surface and extend the handle out enough for the hood to contact it and push it down. then I take it out and measure it's length.

MRM331

Any and all of the above will fit if you design the car around it. Problems seem to occur when someone tries to retrofit a larger intake on a car that was built with a small one (such as stock). All of them are within a half inch of each other. Unfortunately 1/2 inch is all we have to work with.

Keep in mind it's not really the overall height of the intake that matters but rather the design of it. The stock intake is very low on the edges which helps it fit in the "power bulge" of the stock hood. An intake like an original RPM have a very large "log" that may hit even though its the same overall height of the original. Some intakes also are move forgiving when it comes to shaving the upper to lower mounting surface and others are not.

Things I've done:
-Shaving material out of between the upper and lower-RPM, Stock, Explorer GT40
-Grinding down the front most mounting bolt seating surface 1/4 inch-Explorer GT40
-Lowering subframe-all
-Removing crossover pipe and bashing driver's firewall to get engine 1" further back-all

Good Luck,

-Jason

engineer

That would be great. If you could measure from the engine block surface where the distributor pinch bolt is to the underside of the hood that would be great. Also kindly advise what you have done to make it fit. Advise on engine mount spacers, k frame shims, intake milling , hood brace removal etc. Thanks so much...i really want to fit my tfs r intake...but I don't want a hood scoop...its 11 in tall, the gt40 explorer is 10.5 in and the tfs track heat is 10.2 in. So there is 0.8 in across them...i want to see if the tfs r intake will work 😎

MiataDoug

Ok I will get those measurements for you.

MiataDoug

OK I took the measurements and also took some pictures. My spacers that live between the K-frame engine mounts and the Flat plates that bolt to the block are .639", my K-frame is spaced .234 down from the frame. I milled .25" off of the height of my upper intake. I took the measurement from the top of the engine block on the surface the were the distributor hold down bolt threads into. I also used some silly putty to see how much clearance there is to the hood, with the hood shut. I took pictures to document the clearance. Unfortunately, I did not bring a cable I need to post the pictures today. But I wanted to report what info I could today. I will get the pictures up tomorrow. I can tell you that I have almost 1" of hood clearance on the fwd top of the Explorer intake to the hood. were things are tight is the tube coming off the top of the throttle body, and things forward on the engine like the A/C compressor. I am glad I did this for you. I have learned that I can probably reduce the amount of shimming I have on my K-frame. When I post the pictures it will be a lot more help than my description. I put a tape measure in each picture. Going from memory I think the dimension you asked for is 9.25" from the top (as described above) of the block to the hood.

MiataDoug

Here are the pics

MiataDoug

One more thing. While the telescoping magnet in the picture is not standing up straight (It could not because my distributor is installed), the tape measure is standing up straight off the agreed upon surface, and I believe is it the dimension you asked for.

engineer

Thanks so much for taking the time to do this. You have done a brilliant job. It is information like this that allows people to use real data to assess and plan before lifting a spanner. You are a legend thanks again!!! I am sure this will be useful for many people....😊 👍