Standard engine was a 2-barrel 400. You even got an extra 30 hp in your 400 if you ordered the Turbohydramatic, which this buyer did.
Window sticker says 2bbl carburetor and XV code motor, so it's the base base 400 engine for this car - no quadrajet except on the HO 400 and 428 cars, they still used the Carter AFB in '67. It also has A.I.R., cruise control, and the gauge package from the factory. No AC but it has aftermarket AC... I believe this was for sale a while back for a rather pricey sum...
So where did the extra 30 hp come from, if the vehicle in question had 2 bbl carburetion, while equipped with the THD option?
The automatic equipped big Pontiacs have high compression to yield the higher horsepower and torque. They are still a 2 bbl carb. That is the way Pontiac did it in those days. Manual transmission base engine got low comp while the same engine but with high comp went into the auto car. The low comp engine could be ordered with the auto as a no cost option, but that was rarely done.