For 1966, Chevrolet was in its second season of a totally new body change, so mild facelifting sufficed including forward thrusting, blunted front fenders and a revised grille. At the rear, a break with the traditional round taillamps took place. Bel Air and Biscayne featured dual rectangular lamps with back-up lamps built in. Overall length was . The standard six-cylinder engine this year was the larger 250 CID version of . New for the speed set was a Chevrolet Big-Block engine#427 V8 of or . Bel Air was readily distinguishable from Biscayne by its full length body side molding and rear fender Bel Air signatures. All-vinyl interiors were now standard on station wagons while cloth and vinyl trims continued on sedans.