Starting to lean towards it being some type or marine engine. Especially the way the engine mounts are made.I do believe it's a mopar engine but I've never seen one of these. The distributor is in the rear and leans just like a R or RB engine. The oil pump is bolted on the rear of the block also. I can't help you on this one, I'm interested in what it went in also. Something industrial I'm assuming. Hopefully someone will know what it is.
413's and 440's are part of the RB engine family and were used as motorhome engines.oh ok il post more pictures soon but who makes motorhome rb motor
Definitely not a marine engine, those are dry road vehicle type exhaust manifolds, marine engines will either have wet flow manifolds or like some jet drive/race boats just zoomy headers straight up.Starting to lean towards it being some type or marine engine. Especially the way the engine mounts are made.