I've been at 90 in my 261 bored .060 (making about 270ci) with AA-1 2-barrel Holley and Fenton dual-exhaust headers and 3.55 rear and 31.5 radial tires - and a calibrated speedometer. The road was straight and clear AND I check my paints and found no wet spots. This was a one-time deal.
Of course, my brakes are in excellent condition, as are my tires, as are ALL my original-style front-end and suspension parts.
