440 RB engine, new transmission,new bolt pattern...

They make 5 on 4 1/2 rotors for the early disc brake cars with 4 piston brakes. I would keep the 4 piston brakes. Just jack up a single piston and spin the tire it stops from drag in less then a turn.

Then do a 4 piston they just keep on spinning. They stay cooler then the single piston. There is no friction when not applied with the 4 piston Kelsey Hayes, Just like using a Wilwood or Strange caliper.

So that leaves the rear. Just get better BB axles and convert the rear to disc. Now your ready for drag radials,bead locks and front runners.