Editing GMC V6 engine (section)

==Gasoline V12==
===702===
The {{convert|702|CID|L|1|adj=on}} [[V12 engine|V12]] "'''Twin Six'''" had a {{convert|4.56x3.58|in|mm|abbr=on}} bore and stroke.{{sfnp|Motor's|1973|page=852}} It produced {{convert|275|hp|kW|0|abbr=on}} [[Horsepower#SAE gross power|gross]] at 2400 RPM and {{convert|630|lbft|Nm|0|abbr=on}} gross at 1600 RPM in 1965.{{sfnp|Motor's|1973|page=852}}

It was offered in 1960 for the 7000 series trucks, and as a special-order option in [[Canada]]. It was its own separate engine design, based on a single block casting,<ref name='V12Myths'>{{cite web |url= http://6066gmcguy.com/v12myths.html |title=GMC Twin-Six V12 Myths |publisher=6066 GMC Trucks |date=June 1, 2007 |accessdate=2008-10-05}}</ref> which had four [[exhaust manifold]]s, two [[carburetor]]s and [[Inlet manifold|intake manifolds]], and two [[distributor]] caps driven by a single distributor drive,<ref name='V12Myths'/> plus other parts from the 351 V6. A total of 56 major parts are interchangeable between the Twin-Six and the other GMC V6 engines to provide greater parts availability and standardization. It produced {{convert|275|hp|kW|0|abbr=on}} horsepower. Torque was {{convert|630|lbft|Nm|0|abbr=on}}. The 702 was in production until 1966, when it was replaced by the 637 V8.<ref>{{Cite web|url=https://www.thedrive.com/news/40213/gms-final-v12-was-an-obscure-11-5-liter-truck-engine-from-the-1960s|title = GM's Final V12 Was an Obscure 11.5-Liter Truck Engine from the 1960s| date=16 April 2021 }}</ref><ref>{{Cite web|url=https://www.enginelabs.com/news/a-look-back-at-the-702ci-gmc-twin-six-v12-engine/|title=A Look Back at the 702ci GMC Twin-Six V12 Engine|date=12 February 2013}}</ref><ref name=macs-v12>{{Cite web|url=https://www.macsmotorcitygarage.com/inside-gmcs-mighty-702-cubic-inch-v12/|title = Inside GMC's Mighty 702 Cubic-Inch V12|date = 21 April 2016}}</ref> It is estimated that fewer than 5,000 engines were built and that less than 200 exist as of 2021.<ref>https://thunderv12.com/ {{Bare URL inline|date=August 2024}}</ref>