Hard peddle and pulls when braking

It's a 70 Grand Coupe Barracuda.

About 10 years ago i did the from disk brake swap.(73 Cuda spindles with all new part.) Bought a 73 master cyl(i don't remember if it was for manual or power brakes m/c) my car is manual braking car.

From all the reading on this "brake forum section" I'm guessing that i bought a power brake m/c.
Any one know what m/c, piston diameter, worked best for you?

As far as the pull goes, i replace the calipers several time with the most improvement, was the full loaded calipers, but still pulls under a hard braking situation.

It has been some 10 year now, and have just learned to live with it.

My 340 is coming out for a much more powerful 408 Stroker, with forged every thing.
I really need to fix this problem before the new motor slides into place.

Any help would be greatly appreciated.
Author: Cudafever