The Ford 427 V-8 was developed strictly as a racing engine. Prospective buyers were drag racers, stock car racers, and street racers. The engine’s actual displacement was 425 cubic inches (7 L); however, Ford labeled the motor the 427 because 427 cubic inches or 7 liters was the most displacement NASCAR allowed at the time. The motor’s stroke was identical to the 390’s: 3.78 inches or 9601 mm. Bore was 4.23 inches (107.44 mm). It featured a cast-iron block with a thicker deck, which could tolerate higher compression. Cylinders were manufactured using “cloverleaf” molds which resulted in the corners being more substantial on the walls of the cylinders. Nearly all of the 427s manufactured had solid valve lifters except the 1968 version, which featured hydraulic lifters. Many of these motors also had a steel crankshaft; all were internally balanced.
Ford manufactured a side oiler and a top oiler 427. The side oiler was unveiled in 1965. It conveyed oil first to the cam and crankshaft, second to the valvetrain – similar to the antecedent Y-block motor. The 427 top oiler came out slightly earlier and sent oil to the valvetrain and cam first and then to the crankshaft. The engine also featured an aluminum manifold, single or double four-barrel carburetors, and high-, mid-, or low-riser intake manifolds. The 427 remains popular today among Ford fans.
The FE 427 presented Ford with a problem: the motor required tolerances that were difficult to achieve in the engine plants that manufactured its standard engines. This was because of the motor’s 4.23 inch bore. So Ford combined the previously successful 3.98 inch (101.09 mm) stroke and 4.13 inch (104.90 mm) bore in the FE 428 motor, which was an easier engine to produce. Its displacement was nearly the same, and the engine had a nodular iron crankshaft and was externally balanced. The FE 428 was used in cars only in 1966 and 1967: Ford Galaxies, Cobras, Thunderbirds, and Mustangs; and in Mercury Cougars.