79 to 71-72 rear brake backing plate swap???

[MP33]

Need to know if the 79 C-10 backing plates that I have will work to replace the rusted/shot 71-72 backing plates. I just have the backing plates on the 79 rearend, no drums,shoes or anything else. How do I determine if they are 2" like my 71-72 or the heavy duty brakes? I doesn't matter to me if they are the heavy duty or 2" but I need to know what to buy tomorrow. Thanks.....Mike

[MP33]

Update: I measured from the axle face(Where the drum mounts) to the back of the backing plate and the 71-72 is 3.375 and the 79 is a little wider at 3.75.

[MP33]

I do have a 64-70 12 bolt with complete brakes and that one measures within a 1/16" of the 71-72. could I use those backing plates and brake guts from the 64-70 rearend and just get new 5 lug drums?

[72MARIO]

yes you can use the 64-70 backing plates. just throw on the 5 bolt drums. or you can use the 73 up and get the bigger drums and shoes.

[MP33]

I did a little price comparison at carquest and O riellys today. The 73 and up brakes were actually cheaper than the 71-72. So i went that route.