Pontiacs Were Cool

It’s been a generation, almost, since the last new Pontiac was made. That was back in  2010. A lot longer ago than that, actually – because the final run of “Pontiacs” were just rebadged other-GM-brand vehicles that did not have Pontiac engines. One of the very last “Pontiacs” – the Vibe – was in fact made by Toyota. It was a slightly cosmetically altered Matrix and as far from being a Pontiac as Lia Thomas is from being female.

Other examples of “Pontiacs” in drag were the Solstice – which was a re-dressed Saturn Sky – and the Montana/Aztek minivans, which were just re-dressed Chevy minivans with exactly the same running gear as the out-of-the-closet Chevys. Even the much-revered Firebird stopped being a Pontiac, arguably, after the last 1981 model equipped with a Pontiac-made engine was built way back in 1981. It is very easy to argue that the beginnings of Pontiac’s end were sown when the Firebird was reduced to a Camaro with a different (slightly) skin. I speak here as the current owner of a real Pontiac – my 1976 Trans-Am – and the former owner of a number of others. Also as the owner of several Camaros.

I love them both because they are not the same.

My Trans-Am’s beating heart is a 455 Pontiac V8 that is different than the Chevy V8 that was available in same-year Camaros. There is the obvious difference, for openers. A 455 (that’s cubic inches for the Gen Z people reading this, who grew up spoon-fed depressingly androgynous metric ways of measuring such things; i.e., “liters”) is not the same as a 350, which was the largest engine available in a ’76 Camaro.

Not just in terms of displacement, either.

A 455 or 400 or even a 350 Pontiac does not even look at all like a Chevy 350. The difference is obvious as soon as you open the hood – which is part of the reason why you will see the hoods raised at old car shows. Otherwise, why bother – if they’re all the same?

The Pontiac V8 looks a lot bigger than a Chevy small block. It looks almost as big as a Chevy big block. That brings up an interesting thing about the Pontiac V8 – which is that they are all “big blocks” – in the sense that the blocks are all big, even if the displacement is small. A Pontiac 326 (cubic inches) looks exactly like a Pontiac 455. – and the 455 looks exactly like a 400 or a 428. You have to check casting numbers to ID which displacement you are dealing with but they are all basically the same engine. Pontiac increased – or decreased the displacement of its engines by increasing or decreasing the diameter of the cylinders (bore) or increasing or decreasing the stroke; i.e., the length of travel of the pistons within the cylinders The only major internal difference between a 350 Pontiac and a 400 Pontiac is that the 400’s bore is larger; the 428/455 have longer strokes.

What makes this approach interesting is interchangeability. Almost all the external parts – including such things as intake manifolds, timing cover cases, cylinder heads and so on – can be swapped around on any traditional Pontiac V8, irrespective of its displacement. In contrast, small block Chevy parts don’t fit big block Chevys; the two are completely different engines.

It’s easy to raise – or lower – a Pontiac V8’s compression ratio, too. Just swap heads. Most other engines require swapping pistons – which means having to tear down the entire bottom end of the engine. Most Pontiac heads originally installed on 326, 350, 400, 428 or 455 will fit (and work) on any of those engines, regardless of the year they were made. They have difference size combustion chambers, which is how Pontiac altered the compression ratio. My ’76 TA’s 455 has very low compression – 7.6:1 if you can believe it – in part because high-octane leaded fuel was being phased out around in the mid-1970s and engines with high compression ratios tended to “ping” if you used low-octane unleaded. That is part of the reason why the 455 – this huge V8 – only made 200 horsepower back in 1976!

Low compression generally means low performance. The good news – if you’re a Pontiac guy – is that it’s just a matter of swapping out the factory low-compression heads with earlier heads that increase the compression ratio. This is in fact exactly what Pontiac did in 1977 with the 400 V8, which replaced the 455 as the Trans-Am’s top engine that year. A high-performance (“T/A 6.6” on the hood scoop) version of the 400 was offered; among other things, this 400 used heads from a 350 that bumped up the compression by about 1 point, which increased the power by about 20 horsepower. This was a mod anyone could do to their Pontiac in an afternoon, without even removing the engine from the car. Once done, the swap looked factory because Pontiac 350 heads look just like 400 or a 455 heads.

This wasn’t all – but it was a big part of the reason why a Firebird or Trans-Am was not a Camaro or a Z28 with some exterior/interior cosmetic differences, which is unfortunately what the Firebird and Trans-Am became after the end of the 1981 model year. In 1982, GM introduced a new body for both cars and for the first time since they were originally introduced in 1967, they both came with the same drivetrains – produced by Chevrolet. A 1982 Trans-Am is – functionally – a 1982 Z28. Both cars have the same 305 Chevy V8. That made the 1982-up Trans-Am only superficially a “Pontiac.”

This made it superfluous.

GM did the same to its Oldsmobile division, which – like Pontiac – exists now only in memory and in garages like mine, where the TA survives as a relic of that better, vanished time Rush sang about.

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