1967 Pontiac 400 Specs

The Pontiac 400 is one of the performance engines that created Pontiac's muscle car image.pontiac image by Sainte-Laudy from Fotolia.com

The 1967 Pontiac 400 engine was the first variation created from the original 389-cubic inch motor that high performance Pontiacs used in years preceding 1967. The Pontiac 400, with its four-barrel carburetor and high compression ratio, provided thunderous power for the GTO, Tempest, LeMans, Bonneville and a number of other Pontiac vehicles in the 1960s and '70s. The 400 was available in multiple configurations, depending on the vehicle in which it was placed.

Displacement

The 1967 Pontiac 400 engine was based upon the 389-cubic inch motor found in Pontiac vehicles before 1967. Pontiac created the 400 by widening the cylinder bore of the 389 to 4.12-inches, which increased displacement. The cylinder bore of the motor is measured as the diameter of the cylinder from side to side. The Pontiac 400 used a 3.75-inch stroke, which was the same as the 389. The stroke is the total distance the piston travels from its lowest to highest point in the cylinder.

Depending on the camshaft and cylinder head configuration used on the Pontiac 400 in 1967, it could produce anywhere between 255 and 360 horsepower from the showroom floor. Torque output for the 400 was approximately 440 foot-pounds. The 255-horsepower configuration produced roughly 397 foot-pounds of torque.

Pontiac 400 engines, unlike the 389 powerplants that preceded them, came with only a four-barrel carburetor to provide air to the engine. The 400 could be ordered with a special "Ram Air" package that allowed the engine to induct fresh air from a hood scoop mounted above the motor.

The 1967 Pontiac 400 used a 10.75:1 compression ratio to achieve high torque and horsepower levels. The compression ratio is the difference between the lowest and highest volumes in the cylinder during piston travel.