I own both a mutifuel deuce and a civilian Diamond Reo truck with a very healthy 331/ 3052 and I can say 100% that no matter what the charts say, the 331 makes nowhere near the power of the multi. My 331 is a '69 and rated at 171 hp... at a comical, rod throwing 3600 rpm. I would not want to be in the same county as that engine over, say, 3200. Granted mine is a very heavy, extra long straight rig, but its only good for about 25-30mph up hills and 45-50 on flat ground. Thats with a 2 speed axle with 8.5:1 (ish) in low.
Owning both trucks, its a theoretical "what if" I kicked around, but it probably wouldn't be worth it. You could probably hit 5th on long gentle downhill stretches and maybe run on flat ground for a bit at 55... I guess I would do it if I blew the 3052, had a spare 3053 and needed to run it, but I don't think I'd invest in buying parts.