i run the ls3 heads from TSP with a heavly port job done to them milled .015 with a .040 gasket to achieve 11:1 cr. per the pros i talk to.

trenz if you wanna do this setup i can help ya, BUT it can get costly pending on what you already have and what all you need, zippy posted some good info specially on the 2.5 5.3 heads i ran these on my lq9 short block and put down 400+ 404 i think to be exact right now i am knocking on 500 maybe a tad over with a few new mods i done lately i'll be the first to tell you my setup is not cheap, the cam you mention personally i wouldnt use it, the stall is to small, you need 4k at lease then again my opinion.i do have the truck intake and edelbrock fuel rails if you need them dont have injectors or TB but i would get some 42's. theres a guy on quickstreettrucks.com selling some lq9 2.5 ported heads if interested. a proper mill and proper head gasket thickness will net you some good gains, shoot for 11:1 cr if ya need anything feel free to pm me..

 

pm sent

 

I would go with a set of PRC 2.5 LS6 heads. On the LQ4 motor, with the dished pistons I would look for a head with a smaller chamber to try and get some compression back in the motor. The L92 heads are nice and we can mill them a decent amount but I think for the money it costs, I would give up a little air flow in return for the compression. Depending on the cam, you will probably end up making similar power. Let me know what you think or shoot me a PM with any questions and we'll see if we can't get you fixed up!

Thanks!
Jon

 

there ya go right there!! great info jon

but i wouldnt mill the l92 heads to much, isnt it true they have very thin decks? i milled mine .015 to achieve my 11:1 cr with a .040 gasket