Based on the stats I would say the '65, it does have a 200lb weight advantage. I know the older engine is rated at the flywheel, it has around 80-90hp to the rear wheels. I don't know about the '89 engine. -'65 Mustang coupe 6cyl 3.3L -2556 lbs -120hp -190tq -'89 Mustang coupe 4cyl 2.3L -2754 lbs -90hp -130tq
I got 10 bucks on Bell. They'd have to film that race with a time-lapse camera. If I have to pick a car, I'd put my money on the '65. If it's well maintained, that ol' 200 will surprise you. It ain't a tire frier or anything like that, but I doubt very seriously it would have any trouble putting away it's 4cyl. grandson.