I'd contact Hagerty with the engine question. They didn't ask me too many questions, mostly the value of the car and to provide photos. I know they don't want to insure highly modified cars because that is considered a higher-risk class of owners than fully restored original vehicles. If a replacement engine is equivalent to or similar to one offered by the factory I don't see how they could have a problem with that, especially if the car is a nice resto.

I emailed digital photos to my agent, who then sent them on to Hagerty. That saved a few bucks in film and processing. I upped my coverage to $25,000 this year, from $15,000 last year.