The later modle motorhome and pickups 440 motors where designed to tow, they are not anywhere near a pre 1971 hi po 375 HP 440 magnum motor
As far as fitting one of those motors in a 1966 Didge Coronet I'm doing a install now on a original 1966 Dodge Deluxe two door sedan six cylinder 3 speed stick shift car, I pulled the six cylinder K member out of it today and will put the V8 K member in it tomorrow. It will end up with 440 block stroked to 3.91 with a 4.35 bore size and a set of Herb McCandless hog out 452 iron heads and a Eddy RPM Performer intake manifold with a Holley 850 D.P. carb. on it. Nothing exotic, I did have a 4 speed hump put in it so I can use a NP833 O.D. tranny out of later model pickup or van. I bought the steel 1966 to 1972 BB engine mounts and rubber mounts from a local racer that had a set for sale so it will bolt into the 1968 B body V8 K member I bought from another local Mopar guy. I hope to have it running by the end of this summer
I had it painted last year and the interior done this past winter, nothing ever goes as planned
I was planning on having it running last summer Good luck on yours