Well, you would lose that bet. The engine is still made and in dang near every Toyota and Lexus vehicle.
I get tune up parts at Autozone. All other parts are available on my site or from a former Toyota Marine dealer, or from a Toyota dealer or Lexus dealer.
There are a lot of marine specific hot rod parts available for the 1UZFE engine from Australia, they love to pull them out of cars and put them in jetboats down there.
PLUS, you only need 1/4 the maintenance of a typical antiquated pushrod V8, the maintenance interval (oil change) is 200 hrs, plugs 1k hrs, etc. It's a Toyota, not a Mariah. Hey, they don't make those anymore, do they? Bet it's hard to get parts.