as a distinct models. Consequently, the "Valiant" chrome script that appeared on the 1964 model's trunk lid was deleted on the 1965 model in the US market. For 1966, the stylized red-and-blue Valiant "V" emblems were replaced on the Barracuda with a model-specific stylized fish logo. For 1967, the new four-barrel V-8 with was optional only in the Formula S, which boosted the Barracuda's performance with 0–60 mph in 7.4 seconds and the quarter mile covered in 15.9 seconds. In other markets such as Canada and South Africa, where Valiant was a marque in its own right, the car remained known as the "Valiant Barracuda" until the A-body Barracuda was discontinued after 1969. For 1970, the Barracuda lost all commonality with the Valiant as an all-new E-body Barracuda was produced. Duster Plymouth introduced a sporty new model for 1970: the two-door fastback Duster. The same technique that spawned the 1964 Barracuda was employed for the Duster. It was designed to use the same front end sheet metal, running gear, and wheelbase as the Valiant, but Plymouth's stylists gave the car an entirely new look by using a modified fastback configuration with radically curved side glass having only half the curvature radius of conventional side glass. Though the V8 engine with 10.5:1 compression, and of torque had been available for special order in Valiants and Barracudas since 1968, the 340 was offered as a regular production option in the Duster 340, Plymouth's analogue to the Dodge Demon 340 and the Dodge Dart Swinger 340. The Duster was an immediate hit as a sporty alternative to the now larger and more expensive Barracuda. Throughout its production lifetime, the vast majority of Dusters were built with the Slant Six engine (available in 198 and 225 cubic inch versions) and TorqueFlite automatic transmission. An aggressive "shark tooth" grille was offered on the fastback Duster 340 and new-for-1971 Duster Twister models. The Twister was a "performance appearance package" produced in response to increasing premiums on muscle cars, many of which were calculated using the vehicle's power-to-weight ratio as an actuarial gauge. Despite the "dust whirl" side stripes and "Twister" decals, Rallye road wheels, dual racing mirrors, twin hood scoops, flat-black hood paint with strobe stripes, and plaid cloth-and-vinyl trim interior available in four colors, the biggest engine available was the V8. Chrysler increased the displacement of its highest-performance small block V-8 engine from to for