Pontiac was no stranger to V8 engines prior to the 455. The company had been producing them since the mid-1950s, and as the years progressed, those V8s continued to grow with popular engines like the Pontiac 389. The replacement for that engine, the Pontiac 400, had a short but decent run for a couple of years before it and the 428 were effectively replaced by the 455 V8 in 1970.
The 455 was created by boring out the Pontiac 421 Super Duty engine. The Super Duty was an engine mostly used for racing purposes, but Pontiac looked to use this new 455, which now had a bore of 4.1525 inches with a 4.21-inch stroke. This new engine topped out at around 370 horsepower, which may not have been the most powerful engine at the time, but it could also produce 500 lb-ft of torque, which is rather beastly.
Pontiac would use this 455 engine in a good number of their vehicles, from high-performance GTO cars to full-size sedans, and over the next few years, the company would also produce Super Duty and High Output versions of the 455. As was often the case with these muscle car V8 engines, the initial horsepower results were impressive, but the maximum horsepower would gradually decline with each new model year. The emissions restrictions certainly wouldn’t help that in the long run, and by the end of 1976, the Pontiac 455 had its final day in the sun.
[Featured image by Riley via Wikimedia Commons | Cropped and scaled | CC BY 2.0]
