[dad911]

I think you need adapters. TRE motorsports sells adapters/kits, but you may want to do some research, I seem to remember that it uses the original rotors, which won't help with heat. May not be much of an upgrade.

You would be better off asking& searching over at the 911 forum. Also search posts about brake upgrades by user "Bill Verburg"

You also need to be careful with wheels. When you start upgrading calipers, stock wheels may not fit. I'm going through that now trying to fit wheels over turbo calipers on a '73.