Nailheads Nailhead Engine Specifications Buick Nailhead Casting Numbers 425 Identification Oil Consumption - 1964 401 and 425 Cubic Inch Engines Carter Dual 4-Barrel Carburetor Adjustment Carter Dual 4-Barrel Idle Adjustment Buick Dual 4-barrel Carburetors, Linkage Sticking ...
The 1967BuickGran Sportenginehad bigger manifold branches, larger valves, and improved exhaust headers that assured minimumgasflow restriction. Intake valves were 18 percent larger than in 1966 and the exhaust valves were 56 percent larger. There went the old "nailhead." Other innovations included ...
The Nailhead was a 401 cid V8 (officially marketed as a 400) that produced 325 horsepower and a solid 445 lb-ft of torque. It used a four-barrel Rochester or Carter carburetor, five-bolt mains, had a 10.25:1 compression ratio, dual exhausts, and hydraulic lifters. Available ...