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GMC Twin-Six V12 Myths

Myth #1, Its Two V6s welded/bolted together.

Not true at all, while is may look like two engines it not, it is one block, one crank,
one cam. it has four head & exhaust manifolds, two carbs & intake manifolds. Below
are exploded views from the GMC Parts book of the block & crankshaft.

Myth #2, The GMC V12 has no power.

The GMC Twin-Six V12 May be low on horsepower by today's standards, but you must
remember this is a truck engine from the past, true it only has 275 hp, but it boast 630 ft lbs
of torque. This engine was used in the Biggest GMC Trucks, like the 1960 GMC Minuteman
Missile Transporter, try pulling on of these with a Jag V12.

GMC/Boeing LGM-30A "Minuteman I" Transporter, Photo by Hill Aerospace Museum

Myth #3, The GMC V12 has 2 Distributors.

The GMC Twin-Six V12 Does have Two Distributor Caps, but they are both on the same Distributor
Drive. inder the plate are two sets of points, that run two coils, each one if for one side
of the engine, the left for the left & the right for the right. This enigne will run off six
cylinders if you have one side go bad it can be limpped home on the other.

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Information About GMC Truck Drive Trains

	6066 GMC V6/V12 Engine Pages
1960-1974 GMC V6 Engines Page #1	1960-1974 GMC V6 Engines Page #2	1960-1974 GMC V6 & V12 Engine Data
GMC Diesel Engine Page	1960-1966 GMC's Inline 6 Engines	GMC's Twin-Six V-12 Engine!
Carburator Page	GMC V6 Performance Upgrades	Plaid Valve Covers
GMC 351 cid V6 Engine	GMC 478 cid V6 Engine	GMC 401 Magnum V6 Engine
GMC Twin-Six V12 Myths	GMC Irrigation Engines	Powered by GMC V6/V12 Engines
GMC Transmission Data	Spicer 5831-B Transmission	GMC Drive Axle Data

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