Facebook Marketplace is a place of wonderment and what the hell? Today, I bring you the former (but am definitely still open to the nonsense of the latter). So, what’s on sale? An engine of legend, of literal monstrous proportions: the General Motors “Twin Six” V12.
Because of its target audience, though, only about 5,000 of the Twin Six were produced between 1960 and 1965. No one knows how many are still operating today or are salvageable but ThunderV12, which offers a modified 425-hp version of the original Twin Six, guesstimates only 200 remain, many of which are, in their words, “basket cases.”
One that has survived is available for $4,500 in the Casper, Wyoming area. The engine is listed in fair condition and doesn’t come with a starter, but does include a gearbox and transmission. Another example sold out of Ohio for $2,900 last year. That seller, who apparently lost interest in a V12 project, offered only the engine, which was mounted onto a stand with casters for easy moving.
The Twin Six had a short lifespan but is revered for its specs, size, and scarcity. Not simply two 351ci V6s zip tied together; the Twin Six featured a dedicated, single-piece iron cast crankcase that was four feet long and weighed 190 pounds. The 11.5-liter V12 featured four cylinder-heads, four exhaust manifolds, two distributors, two intake manifolds, an oil sump holding four gallons of oil, and a high-volume oil pump capable of circulating 17 gallons.
All this magnificence weighed 1,485 pounds, which was comparable to small cars of the era. You know, before safety and smartphone connectivity became necessities. Despite its massive size, the V12 made just 275 peak horsepower at 2,400 rpm, which probably doesn’t really impress you. The engine was designed as a diesel alternative for workhorse duties, anyway, such as in farming, first responder, military, and trucking sectors, industries where torque was the gamechanger. Enter the GM Twin Six, a low-revving, heavy-hauling engine that produced 630 pound-feet of torque between 1,600 and 1,900 rpm. That’s enough oomph to tow 60,000 pounds up a mountain grade. All on regular ol’ 87 octane.
The Wyoming seller suggests a higher estimate of 1,500 Twin Six engines in existence. There will likely never be a consensus but the it seems any that do come up for sale will be long-term project build. To the right grease monkey, it might not be such a bad price to pay to wrench on a rarefied monster.
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