Well if thats all shes complaining about, you are doing pretty good!! lol.
My friend (now divorced) was married to Voldemort...err I mean a nice girl, that didnt like getting her hair wet, didnt like being in the sun, hated being further than 200 feet from a shopping mall, and absolutely hated when he drank beer.
Other than that, I have twin 4.3l EFI engines (TBi) and people continually comment how quiet they are. Of course, in my 278 Vista, they are deeper down than say your Sundowner, which the engine is much closer to the floor. Maybe add marine grade, fire resistant soundproofing to the engine cover/floor area?