My 1974 Chrysler 318 has white smoke from the starboard exhaust on start up. Revving the engine creates more of the same white smoke. After turning off the engine, there is a sheen on the water that looks to be gas and/or oil. This just started happening after switching over gas tanks. Engine ran all summer on port tank fine. Switched to starboard tank and changed oil and boom- white smoke. Engine had a tune up at beginning of season and my port riser is going bad. Any ideas?