1977 Dodge Motorhome 360, model MB400, I was told just needed water pump, (besides battery and new tires.) My question is...would it be good investment to fix up, have some money to work with. Bit would be all I have. The tires are 800×16.5 is it recommended to keep or can they be safely switched with different size. Please any advice would be appreciated before I make any big decisions. Thank you