Dakzuki wrote:
So how did those early 70s Ford class Cs get built?
I don't know exactly, but all those Dodge-based were the same way.
I can only imagine that the unibody "boxes" that stiffen the floor area and support springs etc. were part of the cutaway "chassis" then the RV upfitter (or a third party like MorRyde now) added the needed reinforcement.
Design is part of a chassis manufacturer's dominance. Back in the early days of Class C, DODGE ruled the roost. Given that whether a 1971 was Chevy, Dodge, or Ford, every one would have been unit body and something needed to be done to reinforce the bare unit body components. So I think there was another factor, alluded to here: Pricing and/or its twin, Financing. In this thread, OP's have indicated that Ford's financing structure is more favorable than GM's. What I "heard" but cannot verify, is that Chrysler fronted their cutaway Dodges to the RV industry. Meaning, the Chassis didn't have to be paid for till the completed RV was shipped. Again, heard but not verified.
Thenallofasudden Dodge was out of the biz. There stood Ford in 1975 with a cutaway on a full truck chassis. That must have been a no-brainer for the RV (and cube van) industry. GM joined in later, but their history is different branding, lower capacities, spinning the product line off and then pulling it back in. To the best of my knowledge, Ford didn't go through all those gyrations, just provided chassis and over time developed very detailed stretching instructions. I'd rather marry a faithful ordinary woman than a cheatin' beauty. Just sayin'.