The 11.8:1 pistons, CNC ported heads, HD valve springs, higher volume fuel pump, HD clutch springs and Carpenter's cams. I retained an air cleaner ( and have taken much abuse for doing so) and kept my Jardine system rather than the Brute ( for which I have taken equal flack)
Carpentered dynoed it at 208 hp and 169 ft/lbs tq.
Before the job, with the Jars and PC III, it had 138 hp and 144 ft/lbs.
If I could only tell you what a difference that 70 hp makes! This is a totally different animal now.
I will most probably go for the Brute system in the future but just don't like no air filter nor do I want the triple K&Ns. I'm not sure what the Brute will do without my opening up the intake sufficiently (nor does Bob Carpenter) but am willing to give it a shot.
I am not Art, not Scott and not really into the 7K+ rpm thing but wanted far more torque and passing power which I have. I think it's magic and am very, very happy with the performance I have.