Anybody know if the 63-66A and 67-72 A body manual master cyl.
pushrods are the same length - if not , which is longer or shorter?

Pretty sure the '67-'72 pushrods are longer, but also almost certain there are multiple different '67-'72 pushrod lengths, depending on brake system (9" drum, 10" drum, disc) and year.

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Too many people who were born on third base actually believe they've hit a triple.

Should we try to collect data and see if we can determine how many
pushrod lengths there are out there? I have an aftermarket single pot
MC for 4 wheel 9" drums on a 1961 Valiant - I also believe this same
aftermarket MC to have application on a 1963 dodge dart - again 4
wheel 9" drums manual brakes.

The pushrod length is 6 1/2" in overall length. Or 5 3/4" from the tip
to the leading edge of the pedal bolt hole.

I got the adjustable brake pushrod from Mopar, and the thing is too long to fit on my 73 Scamp with manual brakes. I had to cut threads farther down then cut 3/4" off the end to make it shorter. Then the pushrod hole for the brake pedal bolt was too small so it was either drill it larger, or get a different bolt, so I got a 7/16 bolt to fit the pedal hole, then got a nylon spacer to take out the play in the setup. Small hassle but it works now!