From what I've seen, most worked over 5.3 heads, even the Stage 1 ones, have been set up for larger bore engines. If that is true, wouldn't the 5.3s little bore shroud the larger valves, negating or possibly even hurting performance? I think that bigger is not always better with these small bores. Now if you step up to a 6.0 or 5.7 then that is a totally different story.

If I were to do something with heads, I'd probably just pick up a spare set of used heads and ship them off to Futral or Bo White for some P&P, keep the stock valves, and maye shave them just enough to bump conpression to 10:1.

 

Yeah, well thats probably what I would do. I see the 5.3/4.8 heads here pretty often for not alot of $$$$. So, I would just pick a set of those and send them off. Thanks for the responses though guys.