Meh, this has been done a lot.

One of my brothers has done this to half a dozen cars. It's pretty easy to do.

First car we upgraded was in about 1985, by adding modern electronic fuel injection (a simple bolt-on kit from Holly) to a 1970 V8. It ran so much better with significantly improved fuel economy.

Since then my brother has done engine swaps on numerous cars (like using other brands of engines - the Honda B series and Toyota Supra engine are popular swaps). His 30 year old Hondas have new engines that run flawlessly.