It's no secret that the Gen...
It's no secret that the Gen III and IV engines have an amazing potential with simple modifications. There is a lot of power to be unleashed by installing a new cam and a set of high-flowing cylinder heads.
On our test subject, a 2001 Camaro SS, these upgrades were realized during an engine build that was completed in 2007. At the time, the budget allowed for a set of PRC Stage 2.5 5.3L heads, while a TRex cam (242/248 duration, .608/.612-inch lift, 110 LSA) punished the valvetrain in daily driver duty. The PRC dual springs were more than up for the task but the factory rockers weren't. As time went on and the engine continued to see high rpm, the monster cam damaged the valveguides and reduced power. A smaller custom cam from Pete Incaudo at V Max Motorsports was installed (232/244 duration, .595/.602-inch lift, 114+4 LSA) to help combat the issue, but the damage was already done. The new cam brought the power down to a more conservative engine speed than the TRex, and picked up a lot of low-end power to make it more streetable.
According to Trick Flow, the factory rocker arms from GM were never designed to be used with a higher-lift camshaft. GM rates the OE rockers for .550-inch lift but this hasn't prevented the majority of LS-engine owners from reusing their factory rockers. The reason why it gets ignored is because it's easier and cheaper to just keep using them and appears to work at first. The potential long-term effects are worn valveguides like we have experienced, or even valvespring and stem failures.
Learning from our mistake, we decided to step up in the cylinder head department instead of simply replacing the worn valveguides. Trick Flow Specialties GenX 215cc CNC heads were chosen for their insurmountable reputation, and compatibility with our setup. The 215cc intake runner was more conventional for our forged 347-cubic-inch LS-mill, so we were confident there would be a healthy power additive. Most importantly, to prevent this from happening again in the future, we wanted to install a set of roller rockers. Crane Cams supplied us with their new Gold Race extruded aluminum roller rocker arms. They came as a kit with Crane 7.250-inch hardened pushrods and were ready to bolt in. The roller tip doesn't cause valve deflection, which is when the rocker will actually push the valve stem to one side and cause it to wear faster. This should help our valvetrain to stay alive longer in addition to being quieter than the factory rockers.
 Our initial run on the dyno...  Our initial run on the dyno showed us exactly what we suspected, a limping engine. Our Camaro could only muster a pitiful 385.39 rwhp and 346.38 lb-ft with a Pete Incaudo-designed Comp 232/244 duration cam and PRC Stage 2.5 5.3L heads. The worn valveguides were allowing some oil into the chambers and affecting the charge and even compression. |  Our solution to this problem...  Our solution to this problem is a pair of Trick Flow GenX 215cc heads that haven been CNC-ported. |  Out of the box, Trick Flow...  Out of the box, Trick Flow GenX 215cc cylinder heads feature 64cc chambers with 2.04 intake and 1.575 exhaust valves on a 13.5-degree angle. We had Trick Flow mill the heads for 59cc chambers to match the previous heads and maintain the 11.2:1 compression. |
 The CNC program that is used...  The CNC program that is used on the GenX heads maximizes the potential of their port design without affecting valve strength. |  These heads are said to flow...  These heads are said to flow around 324/262cfm at .600-inch lift. Pretty stout indeed. |  Trick Flow has marked these...  Trick Flow has marked these heads with "215 CNC" denoting the intake runner size and that they have performed their CNC program on them. They are also available in a more affordable as-cast finish and a variety of intake runner sizes, and even a new six-head-bolt option for use with the GMPP LSX block. |