Posted this over on Tech too being I wasn't sure if I would get a better answer there or here so here it goes.

So here is what I got. Was going to build a iron 5.7 from a 5.3 block and got the results back from the sonic tests. Basically, not what I was expecting so I'm kinda stuck with a 5.3 bore or something close to anyways. The sonic test showed the cylinder wall thickness was all over the place in some areas. I just want to get something together at this point so I'm just gonna get this motor together and run it for a bit I think.

I have a set of older 1.5 stage TEA heads I was going to use on this motor if it was in a 5.7 config. I called TEA and asked if these heads would fit and they said I would have to run a 5.7 head gasket due to how the chambers were ported ect. Would you run these heads on a 5.3 and anything I should be looking out for?

 

Not familiar with the heads but I don't see why not as long as you use the 5.7L gaskets as mentioned. You know Wiesco make's forged slugs for the 5.3L that are on the shelf no waiting.

 

Do you know what cc the combustion chamber is?
Sounds like you have a decent set of heads that should make some power

 

62 or 63 cc I believe.

 

Get 3.8in piston its for it and with like -2cc and run those heads.