65 Chevy C10 rear drum brake woes. please help.

[Gumby83]

Hey fellas, i rebuilt my 65 c10 and put disc brakes up front. i planned to keep the drum brakes in the rear so i ordered a rebuild kit. I couldnt get the rear brakes to work after the rebuild.

Since i put in all new brake lines, hydrobooster and master cylinder i decided it must just have air trapped in them. so i bled them by pumping the brake.
still nothing....

bought a vaccume hand pump, and tried bleeding them like that.
still nothing.

Thought "Maybe the drums are really glazed?" so i used a die grinder with a flapper wheel to sand the inside of the drum.
still nothing.

bought an AC 110v vaccume pump and pulled a monster vaccume on the master cylinder...
still nothing.

I figured "maybe i collapsed the original 65 rubber hose from the frame to the rear axle" so i bought a new one.
still nothing.

So i bought a pressure bleeder. and forced 40psi of brake fluid through the system, bleeding over a litre through the rears.

Still.... Nothing.

I adjusted the adjuster through the slot in the drum each time. expanding it till it dragged hard and i cant get so much as a change in resistance with the brake. i swapped the wheel cylinders to another set...

Still Nothing...

What is going on here? did i rebuild the brakes with the wrong kit? is there a oddball drum or something? I looked for new drums, but couldnt find any with the slot in the front for getting to the tensioner/adjuster. i don't have a hole in the backing plate... i am really close to just buying a CPP rear disc brake kit, but i couldnt run 15 inch wheels then. If anyone has an idea, throught or suggestion please let me know. i am at my ends wit here...