Quote:

The A body linkage provides no additional leverage. It's a 90 degree lever with the same length arms.



I just found this to NOT be true.
There is a crossbar type linkage similar to what is OEM under the dash in disc brake B body cars. There is a 4 1/2" bar with the rod to the booster actually off center. This shows that the power setup does have a ratio less than the manual setup. My measurements are not 100% accurate, but the theory is correct.

I took a spare brake pedal assy. and drilled a hole 3/8" higher, then welded washers on both sides. This moved the ratio there from 6.6 to one to 8.125. It went from 1 7/8" to 1 1/2".
Braking did improve but it still isn't great. I still couldn't skid the tires. The saga continues...