Evan -- Yes, my truck only has brakes on the rear axle. Rustoholic (Dean) knows what year they went to 4-wheel brakes. I'd have to look it up. That's good info about the Merc engine... I'll file that away as it may come in handy. Is that a Ford block?
FWIW, my '72 GMC 9500 originally only had rear wheel brakes. At some point before I had it, someone upgraded it to have brakes on the front axle. It had S-Cams on the front and wedge brakes on the rear ... Yee haw.
