I was considering boring my 5.3 to a 5.7 and using ls1 pistions and rods.
Is this a good idea or would it make the cylinder walls to thin? and would the stock heads for or will i have to upgrade the,? I need some advise or if its even worth it.

 

When I did mine my machinist said there was plenty of cylinder wall left. For the heads you can follow AGEARHEAD4LIFE's channel on YouTube for working the 706 heads over or get a set of 243's. But remember you'll lose compression going with 243's so you gotta choose a piston accordingly.

 

The cost involved makes it not worth it. You can buy a 6.0 for less and make more power without the cylinder wall concerns.

 

The 6.0 does run really well. And if I'm not mistaken come with the 243's.

 

The only 6.0 that came with 243 heads is the ls2
You will gain compression with 243 heads on a ls1.
Basically you would build an iron block ls6 motor

 

Yes I remember now, I was mistaken.
If he went from 706 heads to 243 heads he would lose compression, assuming he made his calculation for compression with the current head he owns and not ls1 heads.

 

Boring a 5.3 to 5.7 specs with ls1 internals you might spend $650 if you are lucky.
If you get better stuff it will cost you over $1500.
You can buy a low mileage 6.0 for $1000 all over the country.

 

706 heads would gain even more compression with the 61cc chamber
243s have a 64cc chamber

 

I think somewhere along the line something got misread here. His current head is a 706. I don't think ls1 heads where ever mentioned unless I missed something.

 

The compression gained with the 706 head will not make the power the 243 head will make because the 243 heads flows a lot more air. Mill the 243 head and raise your compression as well with a lot better flowing head.