I had a pr of Austin Princess calipers in the 90s , sold them on for $250 , they were rare back then! I went the Volvo 4pot setup later as parts are plenty.
Answering the question if they (Princess) bolt up, is yes and a spacer kit for vented rotors as usual.
For monster calipers is raid a 80s Transit van front calipers, that will fit too and are huge....i mean huge !!