When I arrived in Schaumburg, all of the hard parts were ready. We let the car cool down overnight and when I showed up bright and early the next morning, Speed Inc Tech Dan Marks was ready to tear into the LS2. Follow along on our heads/cam swap and see how much power it gave us
Conclusion
But what happened next took the cake: our safety consciousness bit us in the collective ass when we learned that the 2004-only loop we'd modded for use with our ride had contacted the larger BMR driveshaft, unbalancing the shaft to the point where on the nitrous dyno pull, the bad vibrations cracked the M6's tailshaft housing! With the housing peeing trans fluid, our test was over. Speed Inc graciously replaced the housing with a new one, but we were unable to get a follow-up nitrous test done. Still, the heads/cam swap netted us over 60 rear-wheel horses and nearly 25 ft-lbs of torque naturally aspirated, and this is an easy 500-rwhp GTO with a tuned 75-shot. And best of all: with all of the extra power, she still idles and drives smooth. We have a couple more tricks up our sleeves before this project is done--stay tuned.
...and intake and exhaust ports that have been designed for maximum torque and excellent throttle response, as well as good horsepower production. | 
Speed Inc spec'd out a custom camshaft to complement the AFRs: A COMP 234/234 at .050, .598/.576 lift, 114 LSA thumper. | 
LS experts Speed Inc would be performing the head/cam swap at its Schaumburg, Illinois facility. As you can see from the photos, brand and model aren't important to these gear-bangers--as long as it's fast.... |
...We don't hold the Mustangs against them--and if you're looking for a shop to transform your GM into a killer EFI ride, you shouldn't either. | 
Technician Dan Marks tees off on this LS2 by disconnecting the battery and removing the engine covers and the nitrous solenoids. The strut tower brace comes off next, and he zip-ties the solenoid wires and lines out of the way. The air intake's clamps are loosened and it is removed. | 
The plug wires are removed, a fuel line disconnect is used to unhook the driver-side fuel line, and a 10mm socket is used to remove the five coil bracket bolts on each side. The coil bracket assemblies are removed. |