Single or double diaphragm booster?

[d9103365]

I go to order a brake booster at my local parts store for my 75 Fury (318) and they asked me if I needed a double diagragm booster or a single. the pictures of the single booster looked more like what's on the car so I selected that...now I'm not sure sure. Anyone know for certain?

 

[sleepar]

The single was on the small.block and the double which is smaller diameter for the big block cars... most of the time but not always

 

[ga66mopar]

1970 and back disc brakes used a dual diaphragm booster and drums used a single diaphragm booster. Not sure about 71 and later. I would check rockauto and compare the different boosters.

 

[Car Nut]

If you have drum brakes all around, use the single booster, but if you plan to install disc's, buy the double.

 

[sleepar]

No drums on 76... but the dual is the better one.... lot better.....

 

[HT413]

My wife had a single diaphragm and out came our 3rd child. Go with the double.

 

[d9103365]

Ok this is frustrating. I did not think they were interchangeable. Rock auto and other parts providers dont specify one or the other. I chose single because the picture looked like the correct one. The double looked much fatter than what was on it.