If I was at home right now, I would have to go see this in person. Looks like a real honest Riviera for a good price. https://seattle.craigslist.org/tac/cto/d/gig-harbor-1963-buick-riviera-original/7110320845.html
It should have a silver engine and air cleaner in the 63 Riv no matter the engine. The red engine and black air cleaner would make me look very hard for the engine code. Red was only used on the 1966 Nailhead. Then it was on all 425s and the Gran Sport 400 (401) engine.
