I'd be tempted to use a small turbo diesel engine..
Gotta say, I really like that huge vee-twin lump out front though. Too shiney by far, but replace the chrome with some well positioned black or nickel plate & it's a future classic.
A few years back there was a small kit car known as a DRK, which looked very similar to the F type. Sketchy memory, but I think it ran Renault mechanicals for some reason.
A M3W with 80mpg and no loss of performance or character...now that's a dream!!
