I took my '77 van with the stone-stock 318 2bbl out of town. I hit 80 mph well before the marked off 1/4 mile... :D I checked the speedometer with GPS and it was dead accurate at 55 mph. Not sure what it would have shown at 80 mph, but when we brought it home, I did 65 mph and that's what my wife said the mustang showed as well.
