Help me pick front calipers

The larger pistons need more brake fluid to extend. You'll need a larger bore M/C to make them work. I've read that you'll probably need power brakes too. Good luck, I'm going to follow this one to see how it turns out. It sounds like a interesting project. You do know the KH 4 piston system was replaced by a single piston floating type caliper. Maybe the engineers knew something.