It's all a balancing act of everything. Dumbing down the torque and trying to hold on to the power as high as possible. Getting it to set the tires without hitting them too hard, converter, pinion angle, instant center, all are big. I'm in the stone ages with ignition and timing curves, I just use springs in the distributor to delay timing.
I agree with you with the vettes, they took a killer package and then tweaked the rules so the only limiting factor left is the tires. No one is going to catch up.