LS Swap questions

[CLM21]

Well according to an LS book I have.... the gen III 5.3 aluminum block has a stock bore diameter of 3.780" and has a max bore of 3.910". Which is a 3.3mm bore.

[The Dark Side of Will]

Stock LS1 bore is 3.897 (99mm) and GM only rates it for a .010-.015 overbore... the book probably mixed the numbers up between the 5.3 and 5.7.

The only way that would work is if GM used all the same cores for the water jackets between the 5.7 and 5.3, then used the liner to make up the difference in bore. It's possible that they did, but I think it's extremely unlikely. Google probably has some photos that would shed light on the matter.

[CLM21]

You can bore all the 4.8L and 5.3L LS engines to the same max bore as the LS1. They both have very thick cylinder walls.

[Tico Frank]

If you get a 5.3 they are good to go low boost later down the line without lot of internal work. Also if you blow a 5.3 vs an ls1 you just go to the yard and grab another $300 engine vs a $1500+ engine.
I am going 5.3 and if you are on a budget so should you.

[CLM21]

Yeah ^^ what he said. 5.3s can actually take a lot of boost. The guys in this article experimented with a stock 5.3 and it was able to take 26lbs of boost.... which is ridiculous:

http://www.hotrod.com/techarticles/hrdp_1109_stock_gm_ls_engine_big_bang_theory/

[rzerob]

"Gertech" did a L33 swap in his E30. Considering the LM4 and L33 are so similar I would ask him some of your questions. He has a build thread.

http://www.r3vlimited.com/board/showthread.php?t=306302

[garretvs]

Absolutely nothing wrong with the LM4 version of the LSx series of GM engines. Aluminum block, 325 cubes, easy to get hold of. It would make an E30 a rocket!

[kbaszak]

I think lm4 is the route I'm gonna be going. Might upgrade internals to ls1 internals or possibly use 4.8 pistons to up the compression a little bit. I wish there was enough room in the engine bay to possibly go fi sometime down the road but from the pictures I've seen it just doesn't look like it