They added a set of LPE cnc ported cyl heads with 10:1 compression, 2.000/1.55 valves. Peak hp jumped from 413 to 437 at 6600 rpm, and peak torque went from 369 to 384 at 4800 rpm.

Then, they added the FAST LSX intake manifold with the stock TB, and converted to an F-body accessory drive so the intake/tb would fit. Peak hp then jumped from 437 to 458 at 6600 rpm. Peak torque went from 384 to 392, but the peak torque rpm jumped from 4800 to 5800. The ported heads/LSX intake/f-body accessory drive added 10 ft/lb or more at almost every data point from 2000 rpm all the way to 6800. At 5800 rpm, the heads/LSX/f-body accessory drive was worth 44 ft/lbs.