Just went and got a quick measurement, pivot point to push rod 3.5", push rod to center of foot pad 15.5". 19" overall.
Also; you probably know this; but you will be surprised as to how many people neglect to service their brake system ; brake fluid should always be flushed at least every 2 years ; Make sure you flush the old brake fluid completely; If there are any contaminants still in the system it could further deteriorate and damage the seals, brake hoses, and steel brake lines. Always use fresh OE approved fluid from a sealed container
4.43:1 is your pedal ratio &'That's ok for power brakes. 7:1 would be for Manual not power brakes. 5:1 and may develop too much pressure in boosted brakes and a hard pedal effort on manual brakes. 4.43:1 with a heavy foot might be too much for boosted brakes. You should be able to tell if there is a normal and gradual progression from maximum brake to lock up or if the brakes are sorta working or locked with no middle. Next would be a visual inspection of brakes looking for mechanical issues. After that would be calculations of bore size of wheel cylinder to master for over mechanical advantages.
Here's a follow up on my cure for this problem. Go back to my pictures on page one. See that block on the frame rail? After doing some research on the web, I discovered that back in the day that block was referred to as a disc brake hold off valve. What it was doing on the drum/drum donor car, I'll never know. Anyway, after removing that, brakes are all better now. I also installed a new distribution block under the master cylinder just because. Thanks for the many replies, and I hope this might help someone else.