bmatthis1

Has anyone done a LS cast-iron block swap? Like a LQ4 or LQ9?

cvx_20

I'm sure there's more, but this one sticks in my mind for some reason:

Here's how fast 660rwhp Miata looks like on a drag strip - MX-5 Miata Forum

Seems he broke the aluminum block!!

I wouldn't shy away from the iron block. The Ford lovers have been doing it for years. Just offset the additional weight with additional horsepower like he did.

Mike

charchri4

Agreed ^^. I looked at one for sale a few years ago and they make a fine build.

MRM331

Or just use a Ford...

cookerz30

Ok but is there a serious weight difference between the iron and aluminium blocks?
Yes i know its about 80-100lbs but it that enough to warrant the extra $$ and time it would take to get the aluminium over iron. (I've kinda got my heart set on the ls family). For a car that is mainly driven to the tracks on weekends and screwed around with a little on the streets, I'm just wondering if there are any serious downsides to stuffing a iron block into it.

charchri4

^^ In my rather seasoned opinion NO there is no serious downsides. For the vast majority of cars built and for what guys do with them that 100 lbs means nothing. If the cost difference keeps you from building the car it is a total no brainer - build the car!

Did you catch THIS POST? It might help.

cookerz30

Ha yes I've read that post
But its articles like this Power for Pennies: How To Score a 500HP LS Engine for FREE
That make me want to go for the heavy iron block

charchri4

Well yeah I'm not arguing with you I agree completely with what you are saying.

garret

I'm building one now so I will let you know how that goes haha. I'm using the 4.8 LR4, so retaining the good parts of the LS motor and can run the t5 tranny, so extra weight from the block is partially offset by the much lighter tranny. yes I know the engine is further forward and that means the balance will be different but hopefully I can correct a lot of that by playing with spring rates.

V8droptop

I'd still, personally, shoot for an aluminum 5.3. A full pull-out truck motor can be picked up for $1100-2000 in my area. I was about to buy a 6.2 L92 for around $4-5000, can't recall, and then decided to move up in size.

But I ran the docket on the aluminum block offerings, and especially if you buy a wreck and part it out, buying a $4000 aluminum block truck will net you some money back on your part out. One more nice benefit can be scoring E85 equipment on a lot of the flex fuel trucks/vans/suvs.

Whats the bigger plan? Are you looking for a complete pull-out motor, or are you going to buy a donor, etc? Looking around at places like IAAI, copart, and police auctions takes forever, but I have had decent luck going that route as far as price goes. Don't be fooled, though, enough people going their know how to decode vins and can find the aluminum LS motors in the trucks, so you aren't likely to get them for peanuts.

That said, if you go the 4.8/5.3/6.0 iron route, you do get some benefits, such as being able to overbore more easily without changing sleeves, and likely handling more power if you go with boost. Although aluminum motors can reliable make more power than most will ever need.

Any of the smaller LS motors with a good set of heads, cam, and a nice intake will be a fun drive, for sure.

charchri4

Part outs are more work but there is also so many parts you can pick off the carcass and use you never thought you would need. Just yesterday I used the washer pump and one of the steel fuel lines from my donor Camaro to plumb up the windshield washers in the Miata.

The thing that bugs me about the story you posted (and I thought this when I first read the story last summer too) is some of the numbers really seem like a stretch in it. Even at an insurance auction 1300 bucks for a van that new and with that little damage seems pretty low. Granted these things are not like a sports car with a big enthusiasts following to fix them so even minor damage like that usually sends them to the crusher. Which is why all the stars must have been aligned perfectly to get $325 for the doors from the thing. Hell I couldn't give away the doors off my Camaro!

I'm not saying it can't be done but clearly these guys were very well connected and probably pulled in more than enough favors to make these numbers the exception rather than the rule. I also feel like the whole point of the build was just to write and an eye popping story and make a big splash on the net rather than to build a great car.

V8droptop

Yea, the article could easily give people the wrong impression/idea. Kinda like how to the turbo vid on mighty car mods, making turbocharging very dumbed down. Just don't go into a swap with $1300 and expect sunshine and rainbows on the other end.

On picking up a wrecked or slightly beat up pickup, you'll get some decent money on the 4wd drivetrain, xfer case, diffs, trans, and a few other bits, but Jim is right in you will be stuck with a lot of baggage or might hold onto parts a long time, can be a pain. But It seems to be the best way to watch your numbers.

garret

I am currently looking at paying $400 for a running, below 100k miles, 4.8.

I have a good edelbrock intake, and I am going to run a cam as well. heads and different pistons could happen later, but I want to make sure the thing doesn't try to murder me first, I am going from road racing racing a 106fwhp hatchback to a 225-250rwhp miata lol. ...Plus I already had a t5 laying around so free tranny was another big budget factor for me.

V8droptop

I wouldn't worry on the pistons, as the 4.8s use the same nicer pistons in the aluminum 5.3. But if it were me (which its not, no worries) I would at the minimum put on 799 heads (if you don't have them) and I may go as far as getting them ported, or cleaned up, but it may double your engine cost, if you are on a budget, skip the PnP.
LS6 Heads Standard On 4.8 And 5.3 Engines? - LS1TECH
Are you going carb or EFI? Fast 92mm/102mm intake is the bees knees. Not sure a 102 will work on a 4.8.

Either way, you'll have better luck building it out of the car than in the car. But you aren't wrong in wanting to learn to drive it as is before going all in, I don't blame you.

garret

carbed. To switch to fast or any ls1 intake I would need to get ls1 fuel rails, injectors, and etc to not run the truck intake. So carbed takes care of both and is a good deal cheaper than efi. (I got the MSD box w/ edelbrock intake). Heads will definitely happen, just a matter of when. I am still in school and after this semester, I won't be co-oping again till summer which limits what I can do, but I will definitely be able to get it going this winter.

Meierznutz

General Auto Recycling in Rhode Island has 6.0's from GM trucks for $900 up depending on miles ad what you want with it. Great people and the cleanest yard I have ever been in. Huge warehouse with everything cataloged and they unbolt rather than torch everything. No affiliation just a good experience.
As for the cast iron vs Aluminum debate, GM claims the iron vs Aluminum block is an increase of 65#. I can live with that if I have to.

garret

I have a 6.0 with one bad piston ring, but we are planning on putting that in a build for racing in chump car...........with a 1500 pick up

Meierznutz

In a pick up you will never feel the extra weight.

garret

also, it's a pick up, so no one can bump us off trak, just "be bumped" off track. it's effectively a brick wall with wheels. but if we don't use it, it will need a good home. (at the same shop we have a 4.6 that will need a rebuild, its just a bit worn out I think it's over 300k miles but I know it would be cheap cheap cheap...just sayin)

V8droptop

On ls1tech they weighed aluminum vs iron blocks, its over 100lbs difference. I believe the scale over anything else.

As far as heads and this build, I'd say go for the iron 4.8, at 400-500, its perfect for your budget, and I would absolutely get stock 799 heads, which is another 300-400 and that's about all you need. I think the extra 40hp those heads are worth (over and over on ls1tech) and likely more w/cam would be a good idea. Plus, you can grow into them, as they will be your core heads if/when you do a PnP setup.

GL with the build. I know budget builds can be really difficult, the carb setup will def help you keep it cheap.

charchri4

+1 ^^ but the thing I have learned over the years about budget builds is the can be more fun to own. There have been many times I've been to the track with my old LT1 Camaro and out run Z06s and high end Mustangs. Why? Because those guys are afraid to hurt their babies and drive like it. I figure if I put my $4000 Camaro in the weeds it would probably improve it so that's how I drive!

+1 for budget builds!

V8droptop

One guy at BIR was not afraid to hurt his baby, or didn't realize he should have been, and put his new 5.0 backwards into a wall... Same corner I lost it on (too much entry speed), but I recovered alright. Happens...

garret

Just a fact of life going to the track

Meierznutz

Going to the track is like going to the casino.... you don't bet what you can't afford to loose!

garret

^exactly.