4 to 5 lugs
Early series V8 mustangs came stock with 5 lugs If your engine was swapped in there is probably a mix of parts. a lot of parts interchange and can be made to work from the ford small cars of that time periof. Mustang Falcoln fairlane plus later Maverick. Comet Granada Monarch and the Lincoln versaille . There is a lot of specific info posted on the mustang falcoln fairlane sites. also info on how to convert to rear disc brakes using ford explorer . later lincoln town car and fox mustang parts.
those brake parts were common to other years sometimes you can go to a good parts store that has the books and some have a listing in the back of what the part number fits. another way is to go to NAPA or some other web site and check the part numbers for your car then try comparing those numbers listed for something like a fairlane mustang etc .. I have done that when trying to find parts that will work from the wrecking yard.