Need Help With My Brakes!!!!

[1970ChevyC-10]

Hi guys, i got a problem ive been trying to solve for a couple months now. I have a 70 c10 that i put 71 spindles on. I bought new rotors and a cpp proportioning valve for disk/drum. The master cylinder is new. Now the problem im having is that i dont really have any brakes. M pedal is a little stiff but when i press down it goes to the floor. It does stop but barely. I dont know if i dont have enough vacuum for the booster or what, i have the vacuum line going to make intake which is a edelbrock rpm air-gap. Also i have a comp cams thumper cam which says its not suppose to affect the vacuum too much. If i could get some help that would be great!

[sprint_9]

Have you tried to bleed your brake system?

[1970ChevyC-10]

yea ive bleed it at least 5 or 6 times. Is there a difference between a disk/drum master cylinder and a drum/drum master cylinder?

[jd7]

yes big difference

[1970ChevyC-10]

So should i get a master cylinder for a 71 c-10?

[jd7]

yes, disk/drum power master and booster.Bench bleed the master before install.

[1970ChevyC-10]

I need to get a booster too? I cant use the one i have now?

[1970ChevyC-10]

This combo on ebay says its will work for 67-72 trucks disk/disk, disk/drum and drum/drum. Im wondering what is the difference between this one and my stock one, other than the booster size.

http://www.ebay.com/itm/7-Zinc-Power...8ba88d&vxp=mtr

[jd7]

I am not 100 f sure on the booster but its best to match all brake componants
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[1970ChevyC-10]

I think i might get just the master cylinder for now, where can i get a correct master cylinder? i just went on advance auto parts web site and the part numbers are the same between a 70 and 71 master cylinder

[Robznob11]

The differance in the masters is piston size
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[1970ChevyC-10]

okay thanks guys, im gonna try and find a master cylinder