aluminum 5.3 block???

[1BAD6660]

i can get my hands on a aluminum block 5.3 out of a GMC Envoy that was losing oil pressure it was rattling at lil bit at idle with low oil pressure but it still ran very strong(no smoking), is this a good block to rebuild vs a 5.3 or 6.0 iron block, im wondering because im looking to do a v8 swap in my 03 silverado...yall tell me what i should do with it...

[truckinL33]

If it's free, take it.

[1BAD6660]

ok, ya its free, is it any better than a iron 5.3?? what s the diffrences just weight or is there a HP diff??

[truckinL33]

The aluminum 5.3 was rpo code L33, ask me how I know . It came with 799 casting heads, same as 241. It's better than your run of the mill iron 5.3, and it weighs less. I don't know what you're planning to do with it, but it would be a nice heads/cam drop in for any short wide.

[PitchBlackC3]

The aluminum 5.3 was rpo code L33, ask me how I know . It came with 799 casting heads, same as 241. It's better than your run of the mill iron 5.3, and it weighs less. I don't know what you're planning to do with it, but it would be a nice heads/cam drop in for any short wide.

How do you know?

The 799 head is the same as a 243, not a 241. The L33 also has flat top pistons to gain back the compression lost with the 243s.

[truckinL33]

I ment 243, thank you for the correction. I know because my handle on here is truckinL33. Why is it L33? Because I have one in my truck. I'm actually surprised to hear that it came in Envoys factory, that's pretty badass.

[PitchBlackC3]

I ment 243, thank you for the correction. I know because my handle on here is truckinL33. Why is it L33? Because I have one in my truck. I'm actually surprised to hear that it came in Envoys factory, that's pretty badass.

I know that, but you said ask....Compliance is mandatory!
If it is from a Envoy it is a LM4 or LH6 (AFM), not a L33.

[George C]

there are several versions of the aluminum 5.3. the ones found in the trailblazers and etc are more prone to issues with the rought casting they have.

also in the GMT900s they have an aluminum version its a LC9 which has 243/799 on them

if its free then just do a refresh on it or add a 4" crank to it. However its not a capable motor or being bored out. You would have to have it reselved and at that point it could be a 427 if you wanted to spend enought money

[1BAD6660]

ok thanks yall! i was wondering if it would be worth my time and money freshning this motor up or just buy a iron 5.3 or 6.0 thats ready to go, im goin to add a cam,LT's and a nelson tune to whatever motor i choose, so what yall think i should do with my money???

[Frenchy]

You'll actually lose weight using the L33 over the 4.3. So there's that benefit too. If I had the choice I'd go aluminum