Test Driving 1968 Pontiac Firebird 400

The 1968 Pontiac Firebird 400 packed a four-barrel V8 rated at 330 horsepower, though a factory throttle restrictor quietly held some of that power in check until the Ram Air II arrived mid-year with 340 horsepower on tap. New staggered rear leaf springs and optional adjustable Koni shocks tamed the axle hop that plagued earlier pony cars off the line. The changes added up to a 13.8-second quarter mile from a car most people remember for its looks.

Slide behind the wheel of a 1968 Firebird 400 expecting brute-force muscle car thrills, and the first thing that catches you off guard is how buttoned-down it feels at speed. Pontiac had already spent a year learning what its pony car needed to compete with the Mustang and Camaro, and by 1968 the engineering changes weren’t just about raw horsepower anymore. Under the hood sits a 400 cubic inch V8 rated well north of 300 horsepower, but a hidden factory restriction quietly holds some of that power back until Pontiac’s engineers decide to let it loose mid-year. The real story of this car isn’t the number on the spec sheet — it’s what changed underneath the sheetmetal to make that number usable on the street.

A Four-Barrel V8 With a Governor Built In

The 1968 Firebird 400 came with a four-barrel version of Pontiac’s 400 cubic inch V8, officially rated at 330 horsepower at 4,800 rpm and a stout 430 lb-ft of torque at 3,300 rpm. Every 1967 and 1968 400-cubic-inch engine, though, shipped with a throttle restrictor that physically blocked the carburetor’s secondaries from opening all the way — a compromise aimed at insurance and emissions concerns of the era rather than outright performance.

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Ram Air II Arrives Mid-Year

Pontiac addressed that compromise mid-year by replacing the Ram Air 400 with the Ram Air II, which bumped output to 340 horsepower. Paired with a four-speed manual, the Ram Air II-equipped Firebird 400 HO could run 0-60 mph in 5.1 seconds and cover the quarter mile in 13.8 seconds — numbers that held up well against anything else in the pony car class that year.

Chassis Work That Mattered as Much as the Engine

Just as important as the engine work was what Pontiac did underneath. New staggered multi-leaf rear springs, with shocks mounted fore and aft of the axle, cut down on the axle tramp that plagued hard launches in earlier pony cars, and buyers could option adjustable Koni shocks for even sharper handling. Standard equipment included a dual-scoop hood, dressed-up chrome engine components, and a three-speed heavy-duty floor shift, all wrapped around a compact 108.1-inch wheelbase and 188.8-inch overall length.

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