So i'm getting ready for the next step with my setup. Built block and I want to assemble/build it myself. It's my first build, so I want to take my time and good lord willing, I can make it happen. I'm set on removing 80+pounds off the nose, so it's going to be aluminum.

I've already bought a LM4/L33 and it's in the process of being shipped to me.

Still don't know what i'm going to do yet. 327, 347, 362, 383 are my options.

Questions I have, do the LM4/L33 have longer sleeves to help support a 4.0" stroke?

I've found they can be bored to ls1 specs, in fact my book says a max bore of 3.905.

Lastly can the aluminum block handle the stress of 1000whp ? I'd like to have the power to run high 9's every time out (900ish HP) no problem, but be able to snag a nice dyno sheet (1000 wheel) when dyno days come along.

Thoughts? Thanks guys.

 

347 gets my vote. All you need are good rods and pistons.

 

I would go 347 also keep the stroke down but the bore up for the cubes

 

If you're going to bore a 5.3; I'd say start with a ls1 block. The prices have come down a lot since the gen IV engines.

A friend of mine had a 347 with a f1r putting down over 900 rwhp in a 4th gen.

 

I like the small bore engine sizes, especially with boost. But I've had a strong desire for a stroker 362 or even up to a 383. Sonic testing of the bore in the aluminum block would be my guideline though, imo.

 

Any body see or know of issues with these blocks flexin/cracking? Worried about my weight/trans brake/900-1000HP...

Thoughts?

 

ERL does some really cool stuff with the aluminum 5.3 block. May contact them and see what they have to say

 

aluminum 5.3 block always saves on weight too

 

The block pictured appears to be a LH6 block if it is a 5.3L

 

Forged 347, your tu1 cam, prc 2.5 ls6 heads, edelbrock pro flow or holley hi ram intake gets my vote. Should make 1200hp without a problem.