I picked up this 72 GMC 2500 with a 6.2 diesel during the summer: I really like this truck. Fuel economy, combined with power steering, power brakes, shoulder harnesses... and tilt (!) makes it kind of a luxury vehicle to me, compared to my other 67-72s.
When I got the truck, it had these crazy wheels on it which I have to admit did grow on me over time... but they just are not "me", and they had to go. I had some rough 2010 Suburban wheels which I painted up. I got conversion lug nuts, modern centre caps, and installed them. The truck rides much nicer now since these are 17's and the other rims were 20s, and the truck is slightly less of an eyesore. I have some plain steel wheels I am getting sandblasted right now, so these wheels will not be the last word on the subject but I think they are an improvement. I can also now sell those crazy 20s and put a little money in my pocket, I wonder what they are worth.
The issue I have now is that the rear axle is a floater so the caps will not fit over the hub. I have heard of people double nutting the rear wheels: taking a stock lug nut, then putting a conversion lug nut on top to create a spacer. I am just checking to see if that is what most people who have made this change recommend, or if there is a better way to achieve the look that I want.