440 differences??
What type of motorhome? class "C" van style nose or class "A" flat nose. If it is the "C" it will be a 440 but if it is an "A" it could be a 413 being it is a '72 (Mopar still used the 413 in motorhomes until the mid 70's). If it is a 440 it most likely will have a cast crank and if it is a 413 it will most likely have a steel crank which could be used in a 440 block being they are the same stroke.
Chuck