Editing GMC V8 engine (section)

==Non-GMC engines==
===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}}.

===Oldsmobile===
Starting in 1955, for the larger trucks, the [[Oldsmobile V8 engine|Oldsmobile Rocket V8]] was available. In 1955 and 1956, it was {{convert|324|cuin|L|1}}. Power listed for 1956 was 210 hp @ 4200 rpm; torque was 305 lb-ft @ 2400 rpm. For the 1957 through 1959 model years, it was upped in bore and stroke and called the 370. Power was listed as 232 hp @ 4200 rpm and torque as 355 lb-ft @ 2600 rpm.<ref>A History of GMC Trucks, James K Wagner</ref>

===Chevrolet Small-Block===
From 1955 through 2003, GMC shared [[Chevrolet small-block engine (first- and second-generation)|Chevrolet's small-block V8]]. This came in 265, 283, 305, 327, 350, and 400 cu in (4.3, 4.6, 5.0, 5.3, 5.7, and 6.6 L) sizes.

===Chevrolet Big-Block===
GMC also shared [[Chevrolet big-block engine|Chevrolet's big-block V8]] from 1968 through 2009. The company used the 366, 396, 402, 427, 454, and 496 (6.0, 6.5, 6.6, 7.0, 7.4, and 8.1 L) versions.

===GM LS-based engines===
Beginning in 1999, GMC began offering GM's LS-based "small-block" V8 engine in various models. Through the years, engines have been offered in 4.8, 5.3, 6.0, 6.2, and 6.6-liter displacements.<ref>LS based GM small-block engine</ref>

===Duramax engines===
Beginning in 2001, GMC offered the same [[turbocharged]] diesel [[Duramax V8 engine]]s as were available in similar Chevrolet trucks. The engine family was co-developed by [[GM Powertrain]] and [[Isuzu]], and has gone through numerous iterations through the years. Duramax engines are paired with a heavy-duty [[automatic transmission]] from [[GM Allison|GM's Allison division]]. <ref>Duramax V8 engine</ref>