Big Front Bolt Pattern For ’70 340 Duster

Tech Question


Jeff Stendeback, Alton, IL, 1970 Plymouth Duster 340

My 1970 duster is equipped with the factory kelsie Hayes discbrakes. I restored the chassis and drivetrain but am unsatisfied with theride. I have firm feel upper control arms in the front, along with a closeratio flaming river manual gearbox, and custom made leaf springs with a 2″drop and caltracs on the rear. Oreilly special shocks all around. I amwanting to add a rear sway bar, caltrac mono leaf springs, a bigger frontsway bar, billstein shocks, and modern wheels and rubber. My problem is thefront brakes are small bolt pattern (I have large pattern on rear, strangeaxles. Is there a way to covert the front to the bigger bolt pattern withoutgetting away from the factory disc brakes? From what I’m being told, thespindles are unique to this car as well. I don’t want to have to change theentire front suspension and brakes to the 73 up just to run modern wheels.Does someone make a replacement hub and rotor that will fit these spindlesand brakes?



Not that I’m aware of, although early Mustangs (65-66) used the identicalbrakes and were 4.5″ bolt circle. It is possible that those rotors wouldbolt on (possible, not probable!) I am also not sure that the 1st-genMustang used the same 2.81″ center bore (register / hub size) as Mopars. has brake swaps that use the big bolt pattern with the smallUBJ stud.

But…ask yourself: Why did the factory go to larger ball joint studs, wheelstuds, bolt circle, inner wheel bearing, etc? Because cornering loads weregoing up (Polyglas and radial tires, etc) and the margin of safety wasgetting close to zilch. Anything larger than 14X6″ wheels really needs the1/2″ lug studs.

Should you decide to bite the bullet, all the info is at:


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