Pontiac Trans Am 1978 455 V8

Pontiac stopped offering the 455 engine in 1976, meaning this 1978 Trans Am’s big-inch V8 isn’t a factory original, it’s the car’s numbers-matching 400 block, bored and stroked to 455 cubic inches during a full restoration. Edelbrock heads, a roller cam, and a rebuilt Quadrajet back up the added displacement. The result blends genuine muscle-era hardware with modern conveniences like Bluetooth audio.

We thought you might like a look at this awesome 1978 Pontiac Trans Am, that Manns Restoration recently completed. It’s powered by the original, numbers-matching engine, but it has been stroked out to 455 cubic inches. They have also added Edelbrock aluminum heads, a hydraulic roller cam, and a reworked Quadrajet carb. This baby makes mountains of torque. They also completely restored the car, both inside and out. It features T-tops, A/C, and even a modern stereo with bluetooth. It really turned out amazingly well. Special thanks to the car’s owners, who graciously let us film this test drive for you. We hope you find it interesting, thank you for watching!

A 1978 Pontiac Trans Am with a factory 455 shouldn’t exist, Pontiac had dropped the 455 from its engine lineup two years earlier, in 1976. So when Manns Restoration handed back this particular Trans Am with 455 cubic inches under the hood, they weren’t uncovering a hidden factory option, they were building one. The car’s original, numbers-matching block is still in place, but it’s been stroked well past its factory displacement and dressed with modern aluminum heads that no 1978 buyer could have ordered. What does it take to turn Pontiac’s last true muscle-era engine option into something even Pontiac never built?

⚑ Featured Gear

Start Car Conversations →

As an Amazon Associate I earn from qualifying purchases.

What Pontiac Actually Sold in 1978

By 1978, the 455 was long gone from Pontiac’s brochures; the top performance option on a Trans Am that year was the 400-cubic-inch T/A 6.6, offered exclusively on 49-state Trans Am and Formula Firebird models after the 455 HO and SD-455 engines of the early ’70s had already been retired. That makes the “455” on this car a build choice, not a factory spec, the numbers-matching original 400 was bored and stroked out to 455 cubic inches during restoration, a common way to recapture big-block-era displacement using a smaller original block.

Modern Parts, Old-School Torque

To back up the added displacement, Manns Restoration fitted Edelbrock aluminum heads, a hydraulic roller camshaft, and a reworked Quadrajet carburetor, a combination built to deliver serious low-end torque rather than chase a specific horsepower number. The rest of the car received a complete inside-and-out restoration, including T-tops, air conditioning, and a modern Bluetooth-equipped stereo, amenities that let this stroked, numbers-matching Trans Am serve as both a period-correct cruiser and a genuinely usable driver.

Share your thoughts in the comments below.

Republished by Blog Post Promoter