Crew C30 vs C20 differences

[slotard]

My '73 C20 Camper Special has a 14FF, which I believe was also used on the 1 ton trucks and crew cabs. However, the Heritage Center doesn't claim the C20 came with that.

https://www.gmheritagecenter.com/doc...olet-Truck.pdf is the info for the '73, change the url to year of your choice for a different year. For '73, they claim that the C20 and C30 frames have the same section modulus (and therefore shape) and material, and that the Crew Cab frame is significantly beefier than the regular cab (3.84 regular, 7.19 crew). They don't show many differences between 20 and 30, and even fewer for the crew cab.

I wouldn't be surprised if the springs were different on 20 vs 30, but you don't need to swap those if you don't want to.

I believe the 1 ton mounts the springs closer together than the 3/4 ton, so you may need to replace perches on the 3/4 ton axle or mounts on your frame.

I wouldn't entirely trust the specs, as my truck doesn't conform. I'd also advise looking for a SRW 14FF rather than a 14SF, so you don't lose too much capacity.