71 440 Hp rating in motorhome?

Did motorhomes ever have HP motors in them? This guy is telling me he has one that the block is stamped HP, just trying to get some info before I look at it. It's still in the MH so I can hear ir run. It is a 71 pioneer if that helps.

I've pulled lots of RBs outta motorhomes thru the years, & have never seen a 440 in a '71. They've always been 413s up thru '72; then 440s from '73 up.

Of course, that don't mean squat; I've just never seen one..