Whats interesting is when speaking with rebuilders (KARP) of boosters last week I was told by the owner that the parts (internal diaphrams in the booster) have not been available for 30 years! And yet there that some people are stating their boosters have been rebuilt, but it was explained to me that some of the boosters have good internals so they check the booster for leaks change a seal or two and put the booster back together.
So there was discussion that some master cylinder boosters were used out of 1980s Lincoln Continental's. My current booster looks to be the original and possibly a weak link in the brake system if I'm rebuilding calipers etc. So after some research I found dual diaphram boosters in both 7" & 8" diameters are available. Here is one specific option is a 7" booster and comes with a 1" master cylinder much like the Bendix units spoken of in this thread. Here's a link: https://www.speedwaymotors.com...-Inch-Bore,5084.html
There are also some boosters/mastercylinder combos that come with a larger bore of 1 1/8" (SVO Mustang) . I really didn't want to start an engineering project and am wondering if anyone has changed to a booster in a similar size? Pros and Cons of 7" vs 8" and varios sizes of master cylinder bores? What I gather is that a 1" master cylinder is larger than the 7/8's OE master cylinder, and going to the larger bore creates a harder pedal, but if you were to put an 8" booster (more power) maybe that offsets the pedal pressure needed. Interesting also that these boosters also mention that they work with lower vacuum pressures.