68 Dart modernizing?

OK so im new here, my dad has a 68 dart 2dr that has been in the works for 10 years now. He curses the old carb'd 318 he slapped in there and have been tossing around the idea of dropping a 5.2 or 5.9 Magnum w/ EFI...... Simple OBD1 stuff......
STOP
dont ban me just yet ok?
Im just not a big fan of carbs.... we live a little more north than most here im sure, Nova Scotia Canada. Your idea of rust is my idea of nearly mint cars..........
Now, hes has swapped to discs front and has new 1/4's to weld on and fenders ready to install, floors have been redone and new trunk pans installed.
I want him to have something he doesnt have to adjust and clean carbs just to go for a drive now n then. Reliability is key so anyone can drive this thing without double peddaling it to keep it running........
Im not sure he'll ever get it done. I want to get him in gear with this so he can get a chance to drive it more than just around the yard.
Im hoping he will pass it on to me or my son someday.

Any tips, tech on updating the powertrain and suspension to make it a nicer ride.
Im not sure how successful i will be at convincing the old dog to do some new tricks.....