[LongBox]

Nice work, and so great that your Grandpa and your Dad are both working with you, something that will stay with you for your whole life.

Back to the coils vs. leafs: I have had two GMCs from 67 to 72, both half tons, and both came from the factory with coils. A neighbour had a GMC 3/4 ton, and it also came from the factory with coils. The coils definitely ride way better than the leafs (I've tried both), but I think GM faced resistance in the market, as there are lots of guys who believe leafs are a better idea, so for the square bodies, they went to leafs only.

Now that I'm gettin older, I kinda like the coils way better, because of the ride.