[RichardJ]

demian5, your signature says you also have an '86. What do you think of that arrangement with the Combination Valve mounted on the cross member under the radiator?
Check the brake line on both vehicles for an inline coupler on the passenger side frame, under the cab. '73 and up brake lines from the coupler forward would be a direct, bolt in swap.
I used C20, '76 brake lines, Combination valve, flex lines, calipers, spindles, "A" arms and MC in my 3/4 ton '67 and it was a simple bolt-in operation.

I can go to any parts store and get brake parts for a '76 3/4 and I know everything will fit.

The brake lines go through the frame rail, just ahead of the suspension.
THE HOLE FOR THE BRAKE LINE WAS ALREADY THERE IN THE CORRECT SPOT. The hole had to be drilled to a larger size, but the brake lines lined up with it perfectly.
The combination valve is mounted with two bolts. One hole was already there.

I don't know if the pre-73, 1/2 ton already has those holes like the 3/4, but I would sure take a look.

Thread after thread, I see guys using a combination of after-market and pre-73 parts.
Why won't this or an other part fit and why is the brake hose too short or too long?