LS3 West Coast Cylinder Heads Swap - Head Games

Redline uses a thread cleaner (that is less abrasive than a tap) in the block's head bolt holes to ensure a good torque and seal. The head bolts use a proprietary thread pitch of 2.0, which is only found on the head bolt threads.

We were to be complimenting the WCCH CNC-ported LS3/L92 heads with a set of ARP bolts and factory MLS head gaskets. While some believe it is not important to change the gaskets on a low mile vehicle, Howard contends that there is some sort of sealant on the gaskets, which gets left on the block and heads upon removal-necessitating a new set of gaskets to form a proper seal.

The factory head gasket just seems to get better and better with every generation. It's no wonder guys are making over 800 and 900 rwhp with these things.

The ARP bolts are treated to the provided moly lube for an accurate torque...

...to 70 ft-lbs on the big bolts and 23 ft-lbs on the small ones. Just like with the Gen III, the stock bolts are torque-to-yield making them unable to be reused.

The stock rocker arms receive 22 ft-lbs of torque.

Jon treats the stock exhaust gaskets to some copper sealant spray and...

...torques the header bolts to the heads with 18 ft-lbs.

Rather than slowly bleeding the air out of the cooling system, and causing the engine to overheat, Howard pressurizes the system and forces a reservoir full of fluid through the radiator and block. It's faster and safer when you think about it--as long as you don't have a leaky radiator (not likely an '09 C6).

With the LS3 all buttoned up, the C6 went back on the Dyno Dynamics rollers. Despite the size of the runners, the gains were all across the board. It seemed to take a few pulls for the PCM to "learn," but eventually Howard tweaked the tune using EFILive to get rid of some knock at the top end (most likely from the sizable bump in compression) and we had an LS7-shredding 518 hp and 452 lb-ft of torque at the wheels. That's a gain of 36 hp and 30 lb-ft of torque. Not too shabby considering how good the heads are from the factory, and that this is only a stock cube motor.

For comparison's sake, here is how the C6 performed stock versus the cam, headers, exhaust and intake. You can see how the big cam lost some of the grunt down low, and doesn't turn on until about 3500 rpm where it shreds the previous 406 hp and 390 lb-ft peak. Meanwhile, the gains with the head swap were at every rpm.