[mr48chev]

Leegreen did one great job of figuring out what might be the issues.

The lip of the drum that is touching the backing plate is easy to trim down in a disk/drum brake lathe if you know what you are doing. If that was the only issue and you had plenty of room for the drum and shoe to clear on the outer edge that is what I would suggest.

Not knowing what width of shoes you have that issue might be solved by going to the next width down of that size of shoes.

Looking up a 64 Galaxie 500 with a 289 it shows 11 x 2.57 # 264 shoes

Then looking up a 68 F100 it shows 11 x2.31 rear shoes # 263

Looking up the 74 F100 rear I have out here it says that it either can have 11x2 or 11 x .231 shoes on the rear.

Ford doesn't make it easy.

After dinking around with looking for other fixes what I am thinking is the solution is to check the width of the shoes, go down one width Or enough width) to get the space on the The inner corner (#1 that Lee marked) and cut the lip of the drum down to clear the backing plate. That probably means taking .050 or so off that edge and the brake guy should have already done that. It is a simple process after you set the brake lathe up to do it to take a few thousandths off at a time.

You might want to check what width of rear brake shoes match the front brakes you have and match the rear brake shoe width with that. Too much brake on the back of a Chevy pickup can cause the brakes to lock up on the rear before the fronts do and send you into a spin. The drum doesn't care how wide the shoe is as far as how much drum surface it contacts it just wears a tad different. That may save adding and adjustable proportioning valve on the rear brake line to dial the rear brakes in too.

That may cost you the price of another set of shoes but is a lot less expensive than other options . A lot faster time wise too.