M37, our unit in Vietnam had one with a 283 chevy from a M114. Dual exhaust, " Tops" vehicle, would do about 70! Unsure of what happened to it when we stood down. Problems with them are differentals, way to slow for driving around town.
That is interesting; I used to see a lot of restored M37's around, but never driving. Looking at the specs, it seems the M37 had a 5:83:1 ratio, while the WWII jeeps have a 4:88:1. Willys CJ-2A's came in at 5:38:1, but were marketed as more of a farm vehicle.