looking for info about updating to dual reservoir on stock brakes on 66 GMC

I have been trying get the brakes upgraded on my 66 GMC, I have bolted on a 68 chevy dual reservoir master cylinder, and split the brakes front to rear. I have not installed a proportioning valve. the brakes work but have to be pumped once to get it to stop, my questions are, will I need to get prop. valve, will I need residual valve?? every one says put discs on, I didnt want to buy the spindles and all the other stuff, I wanted to keep the drums. it acts like there is air in the lines but I have Bled them several times.
the stock master cyl. worked good but wanted the added safety of the dual reservoir and was hoping that I could keep it low budget as possible. anyone with advice or experienced this swap please fill me in.
here is the Skinny on my truck. 68 327, 600 edelbrock carb, performer RPM manifold,doug thorley headers, turbo 350 built for street, 373 posi rear, all the wheel cyl have been replaced, 68 truck master cyl.
thanks in advance
twoblularry

did you bench bleed the m/c if not they can be vary hard to get all the air out if you didn't get a bench bleeder at the parts store they only cost a few bucks it's hard to get all the air out on the truck because the pedal wont let the piston have full stroke that would be my first thought .....ted

i did bench bleed, and then did it again after i mounted it in truck with the plastic fittings and lines. do either of you think i need proportioning valves?? I will take of the M/C and rebleed it start over..
I adjusted the brake shoes till they drag then back them off a couple clicks. in 81' I was top of my class in votech on brakes, front ends, and auto trannys. but been alot of crazy living since then and my memory isnt what it used to be.
thanks again
twoblu larry

thanks guys, I will check it out, could u post correct way to adjust brakes??
thanks
twoblu larry

the adjustments was the problem, i adjusted them as suggested by the above post and it fixed the problem. thanks.
twoblu