Brake Master Cylinder

[orangeGMC]

I have to replace the master cylinder in my truck. It is a 78 K20 with an 81 body. I want to upgrade my 14FF to disc at the same time. What master cylinder should I get? How do I know if I have a jb6 or jb7 brake system? What would be the best? I will be getting it from AdvanceAuto if you have part numbers handy..

 

[sweetk30]

disc converted my truck and was o.k. stock master . plenty of pedel. and the just look at your master and then look at both of ther masters and get the same one. or get the glove box open and or the innerfender and look at the option tag. will say 1 or the other.

 

[mouse]

I use a stock K20 master cylinder with my 14BFF w/disks, works great. The master cylinder is for a truck with the 11" brakes.