Brake booster rebuild kits.

I took apart 2 Midland-Ross boosters (V-band, easy), one on my 1965 Newport and the other from a 1974 Dart slant. Both were the same diameter shell, but parts didn't interchange. The 65 had a rotted thru rubber diaphragm, right where the vacuum port sits, even though I had installed a charcoal filter in the hose to keep gas fumes from the intake out. I wanted to swap the 65 baseplate to the 74 booster to get the correct 4-bolt pattern for my 65's firewall plate. But, the diameter of the aft piston (slides thru baseplate) differed. Otherwise, internal parts were similar. So, even boosters w/ the same nominal dimensions don't always interchange. BTW, the booster on the Newport was a rebuild via an auto parts, so might have differed from factory 65.