2003silvyls

WHAT IS THE BEST SETUP FOR A CAM AND WHAT DO I NEED TO INSTALL IT? ARE LS 6.0 HEADS COMPATIBLE WITH MY LS 5.3?

woodywoods

The best cam is a matter of preference and your best bet is to get ahold of Comp Cams and let them know what you are wanting to do with the truck and what you want out of it. As far as the heads go. The heads are not what is holding you up. I have a 2003 Avalanche with 5.3 and mine has 243 castings which are the exact same as my 2005 GTO 6.0 liter 400 Horse. Most 5.3 heads are built to nearly the same specs as the LS1/LS2 heads with minor differences like stainless steel valves rather than sodium filled. The areas that are lacking on the 5.3 are the intake, throttle body, and cam. You can get well over 400 horse out of the 5.3 by getting a FAST 102 R/T manifold about $1000 an LS 2 throttle body off ebay around $200 and a cam from Comp $400. You will most likely have to and want to relace the pushrods but I have seen people put a relatively mild cam (around .600 lift) in without and they were ok. You can get them for under $120 a set. You might want to look at some exhaust upgrades.