how many freaking master cyl/ boosters are there?

[BurnoutNova]

ever since i bought my 71 k10 a few years ago ive always been dissatisfied with the brakes. the rears will lock up if i really slam on them, and it just doesnt stop as well as i think it should. its almost as if the rears are the only thing working. i had a 69 k20 and it seemed to stop realatively well for a 4 wheel manual drum setup, much better than the 71 with the power disc/ drum setup.

so i came to the conclution the 71 must have either a bad proportioning valve, or maybe a drum brake valve... which would make sence since drums are self energizing, meaning less pressure to my front calipers which need WAY more pressure than the drums would. so anyway... i have a complete 71 c20 (from a bigblock truck) disc/ drum master and booster setup, so i get the prop valve off of it and go to put it on my truck. the master cyl threads are diffrent between the k10 and c20's and the boosters are way diffrent also. i tried to just put the entire setup from the c20 on my truck, but it sticks off the firewall to far and hits my alternator.

my question is... why are there diffrent master cyl and boosters, and is the one from my bigblock c20 going to work on my k10? and finally, where can i buy factory lines and a prop valve for my k10 master/booster?