I know some of this can be done but my researching is a little confusing. I have a 92 z28 with the 5.7 tpi engine. It has 120K on it. Being that this is just a toy for me I cant afford to throw a lot of money at it. So my Idea is to buy a short block and put my top end on it. will the L98 top end fit on just about any SBC? I would like to go to a 427, but i think i understand that anything over the 383 is a different block? The idea is to put this short block in with the top end and when i have the original 5.7 done to take the top end off and put some different heads and induction on the short block while i finish the original rebuild. then someday down the road the car would end up back to original. and i would have a short block left over i can do another project with.

That said, I am trying to figure out what my short block options are with my L98 top end. Bigger the better. And what kinda numbers in HP will I be looking at running the different SBC options with the L98 top end. I realize that i will be severely limiting the total possible Hp I could get out of it by doing this. But i just cant afford to spend more than a decent SBC short block right now. I figure running it a while shouldnt hurt the short to much and in a few months i can put together some induction and exhaust for it to get more power out of it. I already took out the 700r4 and put a 750 hp rated one in. I have already started a rebuild on the original 700r4 and it will go back with the original engine.

And what is the most optimal rebuild scenario to end up with the original L98 putting out the highest possible HP, but with all the AIR, A/C, Smog, stuff that i have already taken out put back in.

Thank you for any wisdom you can share with me new to this game but it sure is fun.

 

You're pretty much limited to L98 replacements and L31 short blocks or even the ZZ383 or zz4 blocks from GM. Going to a 427 is a different block and would require modifying the heads or new heads all together. World might make a block that could fit what you want but then you would be assembling the engine yourself.

 

You can put your top end on any SBC but whether it works is a different story
The stock TPI is a fixed breathing limitation in itself and there are Hp limits to your stock heads so you end up with a 500Hp short block making 250Hp

The way I see it you are doing everything backwards.

Buy good heads , the exhaust ,the induction now and run it , then build a good short block to go underneath it when you get the folding

 

Do you even need a new short block? Is it burning oil? Showing signs of blow by? Have you done a compression check on it?