I have a 64 polara which came with power drum brakes , so i changed to A body disk brakes on front with stock drums on rear. For a master cylinder i used a dual res. off a 73 challenger power booster is off a big block car off late 60's , (the one that has the lugs on it). My question is my brake pedal is as hard as a rock , you have to two foot it to stop the car!!!! . So i took off the booster to exchange it with one from a 68 chrysler and the rod that goes from the pedal to booster is to short (4"from rod center to back of booster) the one thats in my car is center of rod to back of booster is 5 3/8".Is there any way to swap those rods from one booster to the other??????????? sorry about the long post any help would be helpfull mike

You'd want ~1/8" between the rounded nub and the recess inside the piston. Not sure on what interchanges. did the oe 4 wheel power drums work OK but were inadequate and just wanted to upgrade? If I'm reading this right at 1st the only changes were the discs (up front) and a different M/C (kept same booster & same rear drums) and then it wouldn'st stop w 2 feet on the pedal and your tail up in the air!. That is not a long post . I'd get the rod clearance corrected 1st then see if it is a booster prob