Are all proportioning valves the same?
 

I'm in the process of swapping my 70 k10 to front discs. I've got most of what I need. I've ordered a 72 M/C for front discs from napa but they don't sell proportioning valves. I've seen them hanging on the wall at the other parts store but they not 72 specific. Would it work for me though?

Re: Are all proportioning valves the same?
 

Not necessarily.

Proportioning valves are characterized by meter, split and slope. Meter is how long the front discs are held off so the rear drums can apply, split is the point at which the front pressure and the rear line pressure deviate, and the slope is the relationship of the front pressure versus the rear pressure after the split .

The OEs spend a lot of time tuning these for the specific configuration based on series, wheel base, GVW, brake system and CG location.

You'll probably want to find one that was made for your truck (or is known to work on a similar configuration) .

K