Different calipers on '72 K5 to use '93 factory alloy wheels??

anyone with experience installing 1993 chevrolet 4x4 factory aluminum 16" wheels on 1972 K5 blazer (front disc, of course). i had the centers machined out using original 15'' factory steel wheel as pattern, plus machined out extra 1/64".
rear wheel installed with no problem but something(probably original '72 caliper) is keeping fronts from fitting.
does anyone know if there is a slimmer/thinner caliper that will work? 2 pins/bolts that hold calipers in position are 7" center to center on originals