Tempest buyers could also get a 215 cubic-inch Buick V8 ... but that motor was too heavy for the GTO, so Pontiac beefed up the 389 once again in 1964. The 389 hung around for two more years ...

was available in the Tempest Le Mans for 1963, this Y-body car features Pontiac’s innovative slant-four. It represents half of the division’s larger 389-cu.in. V-8 and displaces 194.5-cu.in.

After developing the 287, Pontiac engineers developed the engine to 370 cubic inches, giving this new engine the name Tempest 395-A ... The 326 looked much like the 389, only with smaller pistons ...