Boy Ken, I'll vouch for that, "rode rougher, used more gas and usually rattled more" I've been working for nearly three years to get mine to where it is and it still has a good ways to go. The rough I think I can help some with clean new springs, the gas mileage even with the stock sized radial tires and a 4.10 gear is right around 13mpg on the average and there is a cyclic vibration that comes in about 40mph that I just can't nail down. Taint tires, wheels, axles, driveshaft, center support or u-joint. All of them have been checked, spun, indicated and what not, and everything checks out OK. I truly believe it's some kind of harmonic flexing of the frame.
Nope you can't find much for the 3600 running gear, I've looked everywhere for the last three years and it's slim pickin's. My front brake drums are on size with about .008" or .010" wear and fit the shoes great, she stops on a dime but, when you brake you can feel a throbbing in the pedal so I'm pretty sure they are a little out of round. I'd replace them if I could find new ones but there just taint nothing out there. Turning to true them up would be fine but you can't find anyone around here anymore that will bond an over size lining to the shoes and arc them in.
But I do like how she sits nice and tall and kinda proud like, parked next to a half-ton.
Denny Graham
Sandwich, IL