proportioning valve

ok I'm running a dual reservoir master and brake booster with disc in the front and drum in the rear the problem I'm using a factory gm proportioning valve out of a 1995 g20 van it keeps feeding right back to the other reservoir and not feeding into the lines does anyone know the front and rear holes on these things or words of advice thanks

 

Not sure if it is the same, but here is a pic of a 85 proportioning valve I installed on my 66 Chevy. Top holes were for the MC and side holes went to brakes. Front was for the front brakes and back was for the rear. Hope this helps!