The V6 seemed like a sensible idea, but it fell a little short in the hurried effort to get in into the line for '75. It was the only engine in the Buick Skyhawk. Shared crankpins meant there was sort of an odd-firing pulse that they had to tune out with motor mounts. By mid-77 the even-fire V6 version was introduced in the H-bodies first, with individual crankpins for even-firing, plus all attendant changes like camshaft & timing.

I have a friend that bought a demonstrator '78 Skylark (like the Nova) with a supposed even-fire V6. As it turned out it was only half true, it had the cam from an odd-fire V6 from the factory, oops! 1 warranty claim fixed it (I think he got a new V6 out of it).

The Monza was sold in Canada, plus the Sunbird starting '76, and the Skyhawk. We never got the Oldsmobile Starfire / Firenza variants in Canada though.

These cars were supposed to come with GMs much-anticipated Wankel engine, but they pulled the plug on the 11th hour. The trans tunnels were high in the '75s because of the planned Wankel engine, plus they ran electric fuel pumps to ease the conversion. The tunnels dropped down starting with the 76s since the Wankel program was dead & buried. This despite sinking a ton of money into the program (which was to include mid-rotary-engined Corvettes). Poof!

Come to think of it, the Vega always had an electric fuel pump.