Super - EZ and similar [Painless], are pretty generic harnesses - I'd strongly recommend you get a harness specifically for your year from one of the places that do repro OEM harnesses, available thru any of the vendors that carry 48 parts - you could prolly even get a good one from the Old Car Centre in Langley (604) 888-4412 - a harness designed to physically fit your truck will be MUCH easier to deal with, and you don't need a 12 - 21 circuit hot rod harness for an old truck with near zero acessories!!
Bill