A couple of points which may be of use.
Mustang II's were, to the best of my knowledge,
never produced with 5-lug wheel hubs, only the standard 4-lug, regardless of engine option. In fact, the newer (Fox platform) Mustangs of 5.0 "fame" were also equipped with 4-lug hubs for their entire production run, with the exception of the
very limited production Mustang SVO turbo in the mid eighties, which had a small 5-lug wheel hub. Dunno if these would work or not.
The newer ('94-present) Mustang has 5x4 1/2" hubs, but the front uses a sealed hub/bearing assembly, much like you'd find on the rear of a front-wheel-drive car, with a slip-on rotor. Completely different than a conventional rear wheel drive spindle/bearing/rotor setup. In short, of no use for this application.
You have a couple of realistic options-First, buy a set of 5-lug rotors from one of the aftermarket suppliers such as Fatman, maybe Heidts, or Classic Performance Products etc which is a direct bolt-on replacement for the stock M II 4-lug rotor. You generally have a choice of F*rd (5x4 1/2") or Chevy (5x4 3/4") bolt circle.
Second option, which may be smarter with a truck, would be to order the complete conversion kit which will adapt bigger GM car rotors and calipers to the stock M II spindles. A little more money, but the brakes should work much better than the stock M II.
This being said, I have a friend who's Dad used to own a '40 F*rd deluxe coupe street rod. He just used the standard replacement M II aftermarket 5-lug rotors mentioned above and was quite pleased with the braking capabilities of the car. To each his own, I guess.
Hope this is of some help to your decision making.
Regards,
Wannabe
