I have a 216 in my '51 Fleetline Deluxe (car) and the whole drivetrain is original. It has a Powerglide automatic tranny and I'm unsure of the rear gears. I put some radial shoes on it and I have no trouble cruising at 60 to 65 mph. It would probably go faster, but I don't want to push it. I have made several 200 mile trips and haven't had any trouble with its cruisability.
