Pontiac introduced its new 350-cubic-inch small block in 1968, placing the powerplant into its Firebird, Tempest, LeMans, and Parisienne models. The Pontiac 350 had a 4.62-inch bore spacing. While advertised as a 350, it displaced 353.8 cubic inches thanks to its 3.875-inch diameter bore and 3.75-inch stroke length. A High Output, or HO, Pontiac 350 variant, available for Firebird and Tempest models, produced 320 horsepower.
MotorTrend provides an excellent guide for visually distinguishing a Pontiac 350 from other GM examples. Pontiac 350 engines use a distributor at the rear of the engine block but off-center to the passenger side. The distributor shaft goes directly into the engine block, avoiding the intake manifold altogether, and there’s a gap between the valley cover and the bottom of the intake. Cranking the engine with the distributor cap removed reveals the rotor spinning counterclockwise. Another significant visual clue is the driver’s side mounting location for the starter and fuel pump.
