[SuperTrooper]

Originally Posted by jamesqf

Huh? GM had it working 40 years ago: GM could have made a plug-in hybrid car 38 years ago - AutoblogGreen

GM worked on the Stirling for several years, but never put out a rolling prototype. The reference from the Car Craft magazine is from an ad for GM. The rolling example of the XP-883 had a 35 cu in 2-cyl ICE.