. These soon evolved into the "Thunderbolts" for 1964. The racing Thunderbolt was a two-door post car, heavily modified to incorporate Ford's new 427 CID (7.0 L) V8 race engine with two four-barrel carburetors on a high-riser manifold, ram-air through the openings left by deleting the inboard headlights, equal-length headers, trunk-mounted battery, several fiberglass parts (hood, door skins, fenders, and front bumper), acrylic glass windows, and other lightweight options, including deleted rear-door window winders, carpeting, radio, sealant, sun visors, armrests, jack, lug wrench, heater, soundproofing, and passenger-side windshield wiper. The cars wore Fairlane 500 trim, and were only offered with the two-door sedan body. This special model, of which 111 to 127 total were made (sources disagree), delivered 657 hp (490 kW) at 7,500 rpm and was known as the Thunderbolt.