who knows how big you can punch those out safely and how long they can stroke??...or just wondering if it would be better to go with the 6.0 block out of a HD chevy pickup...thanks!

 

Cool idea. This is the exact set up I plan on doing in my third gen firebird. From what I understand is you can bore a 5.3 iron block to accept LS1 pistons and rods. that's I think 3.90xxx, or in that range. Make sure the 5.3 is iron though, because the aluminum 5.3s have a very thin wall and unless you plan on resleeving, you can't bore them out at all. Also, the iron block is a little bit stronger so if you plan on going forced induction at any point, it would be a good place to start. People have been boring out their 5.3s to accept forged LSX pistons and rods for a total engine build of under 3 grand. Also, with the 5.3s smaller ports you get a higher compression ration ( people often swap 5.3 heads onto LS1s/2s for higher compression). With this setup, expect ~400-415 RWHP with around equal TQ.

 

I have a aluminum 5.3 on a stand right now that i am gonna put in my 07 silverado. The cylinder wall is huge, can be stroked to a 398 with stock sleeves. These aluminum 5.3 's only came in SSR etc. special edition truck stuff. They came with ls-6 style heads and a ls-6 cam. Before I put the 408 in my Iroc, I had a 6 litre block. Ran a 10.9 on a stock 6.0 litre lq-9 with 150 shot
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complete callies 408 using 6 litre Iron block= 3900bux for shortblock