You're looking to put this on a 3/4-ton pickup. I'd look first at 3/4-ton GM pickups in that short range of years where dual master was required but before disk brakes were standard.
That is going to be '67 or '68 through '70.
When I did my swap I used a master designed for power brakes but did not use a power booster. It has worked out just fine, though I do understand there are some design differences between power and non-power. I was trying to stay with a specific year and model of car in order to match my other brake parts, and my chosen car was not available with out power brakes.
