Perhaps I should rephrase waht I posted. What I meant was that the Dana/Spicer rearend was commonly used with the leaf spring option on the 3/4 ton, not so much that the leaf spring option andated the Dana/Spicer rear. That said, though, virtually all leaf spring 3/4 tons and Camper specials I've seen had the Dana rear. I've seen Longhorns and 1 ton Chevrolets both ways.
