[Ragtop Man]

Zero decking isn't strictly about the volume, it is about forcing the mixture into an area where it will swirl, tumble and burn more completely. So, even if the static compression was the same between and engine that was zero decked, and one that wasn't, the zero decked engine will have lower EGTs, tolerate slightly less octane, and make more power all other things equal.

Changing out the rings and pistons to get a newer, lighter combo is definitely a good move, and before I put knocking rods back in I would check them verrrrry carefully for twist bending or fatigue. New ring combos are especially good, and give you what is basically free horsepower by keeping more bang inside the cylinder.