You did not mention the year or if it is a truck or Suburban/Panel. Six or V8.
I have used Vintage Air. I met with the Old Air Guys last year at SEMA and liked their products. I may try one in the next project.
Vintage Air makes a kit for trucks and uses their Gen II system. This works fine in a small cab. It is also the most complete way to buy it.
If you have a Suburban or Panel you can fit the Gen II super and in both cases still keep a functional cowl vent. In both cases you lose part of the glove box depth. The kit includes a shorten glove box liner or they will sell it seperately.
