The motor in question is called the GMC Twin Six, and it was GM's last-ever V12 to be produced for road use. It wasn't even used in a passenger car. Instead, the Twin Six pulled its weight under ...

The 1960s were friendlier times for American motorists. The national average gas price between 1960 and 1962 was only $0.31 per gallon, and there were no EPA regulations to ruin the fun.

and its very first ones were members of the truck-only GMC V-6 family. Available in displacements from 305 to 637 cubic inches (and a mighty 702 cubic inches for the 12-cylinder Twin Six version ...

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