i am thinking of replacing my 5.3 in my 02 reg cab with a built 4.8(since they are cheaper). i have been told i can turn the 4.8 into basically a 5.7 iron block ls1. is this true?and what do i have to do to a 4.8 to make this happen....cam, head, and intake set up for this would be much appreciated as well....thanks.

 

You can't do that with the 4.8, it has a shorter stroke and longer rods. 5.3 and 4.8 share the same block, but the 5.3 has a longer stock crank then a 4.8. The 5.3 and 5.7 share the same crank and rods, so all you have to do is take a 4.8/5.3 block and have it bored out to the 5.7 bore and use a 5.3 crank and rods with 5.7 pistons and you will have an Iron block 5.7. Heads from any of the 3 motors will work, although the combustion chamber on the 5.7 are larger.

 

i want to eventually run some form of FI to it in the future so i would need lower cc chamber heads right? i was thinking of some 6.0L heads to do this and the 5.7 pistons will be flat top already so that will help....would you port the heads or just run them stock? thanks.

 

Wow a 5.3L to a 4.8L swap. That has to be the dumbest idea ever

 

That's actually the plan I have for my next motor, Iron 5.7 with 317 6L heads. SDPC had a pretty nice budget forged piston kit for the LS1's . I'm going to leave them stock. Parish went a long way with his 408 on unported 317 heads. You just run a little more boost

 

You were a newbie once too

 

Yes, but I don't think I've ever wnated to step down a motor size.

 

goin from a 5.3 to a 5.7 isnt exactly steppin down in motor size......i like the piston set a sdpc and the 317 heads, how about a cam for that set up....about what size were you thinkin on yours?

 

He wants to go from a 5.3 to a 4.8. He was just wondering if he could make the 4.8 a 5.7...

 

This statement threw me off then.