Only 1 year did Pontiac use 6 quarts, 1967, 6 in the pan, and 1 in the filter. In 1970 I worked at a Pontiac dealer on the grease rack while doing co-op in my last year as a senior in high school/auto mechanics, and that was one of the things I learned early on from the old timers.............
It was important that you marked 7 quarts on the work order so the dealership didn't loose a quart on the sale of parts.
1967 was the first year that Pontiac wenrt from the long PF7 filter to the shorter PF24, the common size sold today. Back in the day everyone that was paying attention opted for the older design PF7, because we thought it was better for the engine. In reality the only thing gained was more filter area, so there likely was a little less pressure drop with the longer filter. You'd also gain a little more time if you tended to neglect oil changes before the filter went into by pass mode.
The pans were not different, the oil gauge/dipstick, was marked differently than 66, or 68. I have never seen, or heard anyone explain why Pontiac engineers increased the oil capacity in 1967. The one good thing is it was proven that you can run the oil capacity over full on all the other years of engines to bandaid oil starvation under high cornering loads (oval track, road racing) without foaming the oil.
