Show me 4 barrel kick down linkage 74 dart sport - picture attached

If it were me, I'd get a Bouchillion or similar cable set up and call it good

All he needs is the correct rod. Seems like a much easier swap that starting over with an aftermarket setup. Take about 5 minutes to swap and he wouldn't even have to get under the car. The cable setup would involve jack stands and a fair amount of monkeying around.