Thread: You guys are the worst

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Firebird, in 1975 the CAFE rules had the factory engineers scrambling to meet new emission and mileage rules, and they threw everything plus the kitchen sink at those engines, severely limiting their horsepower and torque ratings making them gutless wonders compared to '72's. I think you'll find that the Pontiac 455 was only available for two years, '73 & '74 in the Formula and TransAm so if you've got a 455 it's a transplant, I believe. Likely it's a 400, and something like 185HP rated. '75 was the first year for catalytic converters which plugged faster due to the oils used at the time; plus EGR (also tended to carbon up and fail) to slow the burn speed in the chamber to limit NOx; and severely retarded timing. Some (Ford for sure) retarded the timing at the cam gear making it impossible to advance into '72 ranges unless you re-indexed the cam with a different gear. They also had all kinds of vacuum switching going on to change things based on load. All in all, they were trying to figure out a new ball game, and it was a learning experience that we suffered through as consumers.

It's not surprising at all that you're less than impressed with the performance of the '75 if it's still relatively stock. As you say, there's a lot of potential there, but you need to do your homework. Some light reading on the history - https://en.wikipedia.org/wiki/Pontiac_V8_engine#455