I've alway liked the older impalas...classier than anything available today and still looks bada$$ being 45 years old. I put a lot of highway miles on my car and I just don't want to be peeing the money away, putting money into a new car that isn't going to last (and have the miles rack up quickly). The 4BT is bullet-proof, it can go 500k+miles between rebuilds, it's cheap to rebuild (sleeved cylinders, nitride coated internals so no other machining), and there are guys using them to push 3/4 ton suburbans getting 30+ mpg...I think one of my dream cars (67 impala) with a diesel would be an ideal daily driver, so I'm gonna try.
Looked at a few so far that had either been restored or were survivors (all matching numbers) but I don't want to do a conversion like this on a matching numbers car...it's sacralege in my opinion so don't worry, I'll be fixing one up