By 1955 the US and Canadian Pontiac lines had diverged almost completely, with the US models positioned as "mid-market" cars available exclusively with the new 287 in3 (4.7 L) Pontiac V8, while in Canada the brand was still positioned as an entry-level marque. The Canadian dealership lines were either Chevrolet-Oldsmobile-Cadillac or Pontiac-Buick-GMC; small towns usually had only one or the other, but not both, so it was imperative to keep Pontiac prices competitive with Plymouth and Ford (and Chevrolet). Producing two entirely separate engine series would have increased costs, so the 261 in3 (4.3 L) Chevrolet straight-six replaced the Pontiac Flathead Six, and the new 265 in3 (4.3 L) Chevrolet V8 replaced the old Pontiac straight-eight.