The brakes can't go wider in the outboard direction. If they did, it would push the wheel/tire further outward into the wheel well lip with the increasing brake width.
The difference is offset increasingly inboard by the backing plate. Wider drum has to have matching deeper inboard offset backing plate.
That's what I thought. Is there a difference between the 1-3/4, and 2 because they are so close? I have both, but, have not compared them side by side yet; the 1-3/4 are still on the vehicle. However, I would like to upgrade to the 2-1/2, because I'm going to put the KH CSRP disk conversion on the front, and did not financially want to go with disks on the rear. Any idea where I can find 2-1/2 backing plates??
Whoa, I guess I should have looked at your link first. I do have the parts to put on the Versailles brakes, front and back. I have the magnum 500 original ford rims and the versailles center hub diameter is too large (front and back), and may also interfere with the id of the rims. Not to mention that the caster angle and tie rod end differences, and the consequent need for an alignment. My 9" rear is out of a 70 cougar, I have a 66 cyclone, and what I am finding so far is the the perches from the cougar are about 3/4 of an inch per side inboard, which, may mess with the leaf spring geometry. The 2-1/2 inch rear drums I think would be a good alternative to disks. After all that's what they put on the Shelby's.
SOmeone may be able to clarify this but I think you can get the 2 1/2" backing plates off some trucks and vans but don't know which. Also some large full size Ford cars too. Hopefully someone has a list of applications?
Hmmm. The aerostar thing is interesting, but, I probably can't use just the backing plates, and would need to get aerostar specific parts to load it with, including the drums; and what about the bolt pattern and offsets? The vans, trucks, and full sized cars generally came with the larger bearing housing. So, it seems, I am still in search of 2-1/2 backing plates for the small bearing rear. I've seen end to end dimension lists, but, does anyone have a list of perch to perch dimensions for the 60's cars?
cramer, thanks for that link, good info. The problem is being in north jersey, most of the junk yards have cleaned up, and the 80-89 vehicles are all but gone. I found this link Shelby 2 1/2 “ rear brakes - Mustangsandmore Forum Archive , which has more good info. The one guy used the aerostar brakes but still used 66 backing plates. rbohm, could you expand on that? Napa still offers the drums and parts to stuff the 66 with, so, that's not a problem. I've called most of the mustang parts places along with some cougar places. If they do have them it's only the 1-3/4 or 2". I know I will have to relocate the pearches, but, someone also told me that the 70 cougar rear was about 1/2" per side wider. Which does not make sense to me because the axles supposedly interchange. At any rate, my next question: will the backing plates off a 66-73 bronco fit?