The proper van-based (Class C) motorhome/commercial chassis-cab van, the CB300, was introduced in late '72 as a '73 model. The biggest engine available in it was the 360 until 1976 when the 400 was made an option. The 440 came online extremely late in '76, so much so that it's not even shown in the original printing of the '76 parts books--supplemental/replacement pages were provided. The 440 lasted only into '79, being rare in any of the four model years but nearly non-existent in '76 and '79, because of its late '76 intro and early '79 demise. The '79s were using leftover '78 engines and due to emissions were cancelled prior to January 1st.
Prior to '74, the largest engine available in the standard M-series (Class A) motorhome chassis was the (surprise!) 318, while the larger RM350 motorhome chassis--30-foot and up--was available only with the 361-3 or 413-3 dump-truck engines. In '74 the RM350 became the MB350, which along with the M300 and M350 were available with only two engines: 318 or 440. The 440 remained available until they ran out of 'em (in 1980) in the larger chassis, because it did not suffer the same GVWR emissions restrictions of the van-based chassis.
Big-block CB vans are rare enough that when I asked about the one that had my 440 in it, the junkyard owner had assumed it was not only a small-block but actually a 318. He'd never seen one with a 440 until he went out to remove the engine for me. There were five CB300s in there at the time, and that yard has been in his immediate family longer than I've been alive. I was surprised to find a 440 in it myself, as I don't know that I'd seen one before that day either. That one was a '76, and going by date codes on various parts of the engine, it was likely a June or July of '76 build.
The motorhome pictured here would be a "hatchet van" meaning the builder literally hacked off the rest of the van body themselves, since there was no chassis-cab van offered in '72. So the biggest engine it could possibly have would be the 400, as no B-series van got the 440 until '74. I would put solid money on this being either a 318 or 360 (neither of which was available with a four-barrel), as most RV builders only opted for the bigger engine when it was necessary to move the beast. Base engines kept costs down and most often did just fine in Class C applications prior to the advent of emissions restrictions on heavier GVWR vehicles--half-ton Dodge trucks didn't get catalytic converters until 1979.
1972 Dodge B200 - $12,500 - Redmond, OR - Rare and pristine 1972 Cayo Motivator on Dodge chassis, auto. Serial #5, built by the folks who built Avion. 25,000 orig miles, new plumbing, stool, Marmoleum flooring, memory foam mattress, window screens, stainless water tank, oven never used, curtains, folding/bed dinette, carburetor hoses, belts, good tires, tuned, ball joints and front end, refinished cabinets, sub floor, roof vents, battery, new Emory foam mattress, window screens, Ready for those vintage rallies and more. You won't see another one! This coach runs and drives like new we have found no rust issues only minor surface rust ( please see pics ).
