Started with the same car, also converted to a V8 and I now have 4 way power disc and a Ford 9" rear (small bearing). CSRP up front, Right Stuff Detailing rear disc brake kit:
I don't have that brakes dialed in just yet, but both kits are quality parts. Still dreading getting the parking brake to work.
When I was looking at options, there was a lot of people running a junkyard swap of a early 2000s Crown Vic. I'd consider going that route the next time around.