I have an gen I 400 block, that I was gonna use for a large cube N/A build-up. However, now that Ive been convinced to do a TT system, I really dont think that a 400 will take any kinda real boost pressure. Anyone disagree?

Im pretty sure an LT1 will take boost better than a gen I 350 let alone the 400.

Anyway, I found a guy that has an LT1 block that I could get for a reasonable price, and I think this might be advantageous for me to use, since I was considering going with an LT1 intake anyway, and if I use an LT1 block I wont be required to modify it to fit a gen I block.

However I have a few concerns.

1. Internals. Do LT1s, and Gen I small blocks use the same internals. Like if i buy a crank, or rods, or pistons for a gen I block will they fit an LT1? Camshafts are the same arent they. In fact wont this save me money since i wont have to use retro fit roller lifters for an LT1 block?

2. Heads. Namely compression. I know LT1s use high compression ratios. Are pistons made to drop that down to around an 8.5 to 1 like it would need to be? How well would a set of well ported LT4 heads work for a turbo system? And how much more money do aftermarket heads for GenIIs genrally run.

3. Headers. Basically the same as question 1. Im buying the S-10 conversion headers to make the turbo manifolds, and I need to know they will bolt up to the LT1 block?


Ill probbaly come up with more later.

 

1. cranks are different, you'll need one for a 1-piece rear main. Pistons and rods, oil pumps interchange. LT1's use a cam with a front retainer, but you can use an old style with a cam button. The stock lifters aren't the best for high performance, and aftermarket hyd rollers are pricey.
Oil pans are the same as the later model roller blocks. Diff timing chain and water pump. Balancers are diff.

2. depending on rod/stroke, you can get them down to around 9-1 with off the shelf pistons, or AFR makes heads with 76cc chambers. There is room if you do some mild chamber work to get the stock heads to around 60 cc (mine with off the shelf TRW pistons and LT4 heads should be around 9.3-9.4-1) LT4 heads should work pretty good (I hope! )

3. header bolt pattern is the same (I also used S10 swap headers, upside down and modified a bit )

 

Ok thats good, there really isnt a notable price difference, in the 2 and one peice rear main seal cranks. I wasnt planning on using stock lifters, but its still much cheaper to buy roller lifters for roller blocks than retro fit ones.

I was kind worried about that, and not being able to get the compression ratio low enough. I really dont have the $ for AFRs, with all the other stuff I have to buy. I mean even the LT4 heads arent gonna be cheap. Thats the one big reason I wanna go with the Gen I block cause I can buy nice iron aftermarket heads for under $1k.

So you have already gone through the process with the S-10 headers? Are you on AIM or anything? Id like to talk to you as I havent started mine yet, and maybe you could warn me of some problems I may run into.

 

Sorry, no access to AIM or anything like that. I am offshore and the company has a pretty active firewall, and doesn't allow us to install any software on the 'puters.

You can email me at texlurch@yahoo.com, and I'll try to get back with you..

there are a bunch of pics of the buildup on my techpage also..