Need help identifying a 318. Its in a 1970 Dodge Travco Motorhome . I was told it could be an industrial 318 and completly different as far as intake etc ? How can I tell what I have ?

413 RB Industrial motors had different heads and intakes, but I've not seen any small block Mopar with different appearing heads or intake, Some of the big trucks with a small block did have a carb with a governor on them, but I would be surprised to see a motor home with a governor carb. The governor carbs were usually reserved for big trucks hauling heavy loads so the carbs didn't shock the drive +train and cause breakage. Of course the 340 TA or AAR came with the 3 2bbl carbs.
But we are talking about 70s Mopar, there is no such thing as never. If a customer checked the right boxes when ordering, Chrysler would put pretty much anything any where, if the customer was willing to pay.
Lets start with the basics, is the distributor in the front of the motor or at the rear? Gene

One item to look for is the intake manifold crossover. Light duty will be exhaust. The heavy duty industrial models will have coolant passing through. Easily identifiable by the coolant plumbing. There are many other differences but this is the quick visual one.

One other item is spark plugs. the HD 318-3 are 18mm.

Im told the RV used Marine engines. It looks to have a line from coolant t stat housing to imtake by carb.

RV'S did not use marine engines as well as marine use did not use RV engines.. They may of both been industrial in nature but they each had other components for their intended application. The picture you have is a 318-3 industrial application. Easily identified by the intake and front water pump assembly. You can not use a conventional intake on these heads.