If you want closer to stock but don't mind a newer Quadrajet, I am enjoying my later model Quadrajet with electric choke from
National Carburetors. It is model number ND4478 for 1981-86 trucks. They make remanufactured ones (that I have) and they now have new ones. I am using it on my original 1969 hot slot manifold. That is the type that StingRay mentioned above and I use the special composite and metal gaskets with it, and the heat passages have been plugged on mine. So if you end up with one of those it is workable.
http://67-72chevytrucks.com/vboard/showthread.php?t=762751
http://67-72chevytrucks.com/vboard/showthread.php?t=765690
.