accept a front engine mount as required for their truck applications. 255 In the late 1970s an urgent need to meet EPA CAFE standards led to the creation of the version for the 1980 model year, essentially a 302 with the cylinder bores reduced to 3.68 in (93.5 mm). The 302 was to be phased out and the 255 was to be an interim engine which would remain until the new V6 was in production - a quick fix. Rated power (SAE net) was 115-122 hp (86-91 kW), depending on year and application. Cylinder heads, which were specific to this engine, used smaller combustion chambers and valves, and the intake ports were oval whereas the others were all rectangular. The only externally visible clue was the use of an open-runner intake manifold with a stamped-steel lifter valley cover attached to its underside, reminiscent of previous-generation V8 engines, such as the Y-block and the MEL. It was optional in Fox-chassis cars including the Mustang and corporate cousin Mercury Capri, Thunderbird, Fairmont, and standard equipment in the Ford LTD. Some variants (i.e. Mercury Grand Marquis) were fitted with a variable-venturi carburetor which were capable of highway fuel economy in excess of 27 MPG. Due to its dismal overall performance the 255 was dropped at the end the 1982 car model-year with 253,000 units manufactured - 302 production continued and the plans to phase it out were dropped. Applications: 1980–1981 Ford Fairmont 1981-1982 Ford F-100 1981–1982 Ford Granada 1981–1982 Ford LTD 1980–1982 Ford Mustang 1980–1982 Ford Thunderbird 1980–1982 Mercury Capri 1980–1982 Mercury Cougar 1981–1982 Mercury Marquis 1980–1981 Mercury Zephyr 5.0 H.O. The 1982 model year brought a new 5.0 High Output variation. Manual-transmission equipped Mustangs and Mercury Capris were first equipped with two-barrel carburetors (1982), then a four-barrel Holley carburetor (1983–85). The block was fitted with revised, taller lifter bosses to accept roller lifters, and a steel camshaft in 1985, and electronic sequential fuel injection was introduced in 1986. While sequential injection was used on the Mustang beginning in 1986, many other vehicles, including trucks, continued to use a batch-fire fuel injection system. The speed-density based EFI systems used a large, two-piece, cast-aluminum manifold. It was fitted on all engines through 1988, after which year it was phased out for a mass-air type measuring system in most applications (non-California compliant Panther platform cars retained the speed-density system until the Lincoln Town Car received