Z06 heads are going to bump the compression on your truck too...smaller combustion chamber (64.45cc) than on the LQ4/LQ9 motors (71.06cc). Intake and exhaust port volumes are the same at 210/75cc's respectively. Any '02 and up LS6 head is going to get you sodium filled exhaust valves but that doesn't buy much in a motor that doesn't see extended high rpm running. Any performance gain at all is going to come from the marginal increase in compression ratio.
Sell the LS6 heads and put that towards a good set of ported LQ4/LQ9 heads.
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MSeeb:
If you add the headers,cat back exhaust & aftermarket intake that should add another 40-60hp. </div></BLOCKQUOTE>
I'd love to see the intake, cat-back and headers that are going to give me that kind of power.