John, Rich and group:
I was able to inspect a Ram K today as well as a 64 manual brake Newport.
Both cars had the "two-hole" pedal configuration for attaching the master cylinder pushrod.
The manual brake Newport utilized the upper hole on the brake pedal. The firewall reinforcement plate
mounts the master cylinder approx 3" up from the bottom of the plate.
The Ram K utilized the lower hole on the brake pedal. The firewall plate mounts the master cylinder approx. 1-1/4"
up from the bottom of the plate.
Note also that neither of these firewall plates would work with a power booster. The mounting holes are not spaced to do so plus the booster requires a much larger hole for the pushrod and the manual masters aren't large enough to fully cover that particular hole.
So there are at least 3 different Firewall plates for the 64s.
It is hard to tell exactly while lying on my back in a footwell, but I'd be willing to bet that all the 64 brake pedals are the same.
John, you were right about the upper hole being correct for the manual brakes !
Hope to have some photos for Bob Merritt to post.