Editing GMC V8 engine (section)

===Pontiac===
Prior to developing its own engines, smaller GMC trucks used the [[Pontiac V8 engine]]. They used the Pontiac {{convert|287|CID|L|1|adj=on}} engine for 1955 and {{convert|316|CID|L|1|adj=on}} engine in 1956, but advertised the engines as the "GMC 288" and "GMC 316". They used Pontiac's {{convert|347|CID|L|1|adj=on}} in 1957. For 1958, GMC reduced the bore of Pontiac's {{convert|370|CID|L|1|adj=on}} to {{convert|3.875|in|mm|abbr=on}}, resulting in a displacement of {{convert|336|CID|L|1|adj=on}}. (In [[Canada]], however, GMC used the [[Chevrolet small-block engine (first- and second-generation)|Chevrolet small-block engine]] rather than the Pontiac.) For 1959, as the Pontiac engine's stroke was lengthened to {{convert|3.75|in|mm|1|abbr=on}}, a further bore reduction to {{convert|3.78|in|mm|1|abbr=on}} was done to keep the displacement at {{convert|336.7|cuin|L|1}}.