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GMC 478 cid V6 Engines

All rating are for first year engine was used, many got bumped up in Horsepower & Torque during there run.

Engine Model	Gross Horsepower	Net Horsepower	Gross Torque lbs. ft.	Net Torque lbs. ft.	Bore - Stroke	Displacement	Compression	Notes
478 V6	235 @ 3200 rpm	206 @ 3200 rpm	440 @ 1400 rpm	400 @ 1400 rpm	5.125 in. - 3.86 in.	477.7 cu. in. (7.8L)	7.50 to 1	10
478M V6	254 @ 3700 rpm	225 @ 3400 rpm	442 @ 1400 rpm	410 @ 1400 rpm	5.125 in. - 3.86 in.	477.7 cu. in. (7.8L)	7.50 to 1	12

Engine Application (Notes)
10. In 1962 the 478 V6 was introduced for use in the 6500 series trucks.
12. M = Magnum series engines introduced in 1966.

The biggest V6 Engine GMC every built is the 478 cid V6. This one was a pump
engine set up to run on natural gas. It came from a Texas Farm.

This engine is just about complete & mounted on a stand.

This would make a great engine in a pickup or one ton, they came stock in the 6500 & bigger GMCs.

The 478 has 235 horsepower @ 3200 rpms, & can put out 440 ft. lbs. of torque @ 1400 rpms.
This engine has the standard round truck type flywheel housing & could be mated up
with a 13 speed trans or Allision automatic.

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Information About GMC Truck Drive Trains

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1960-1974 GMC V6 Engines Page #1	1960-1974 GMC V6 & V12 Engine Data	GMC's Twin-Six V-12 Engine!
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GMC 478 V6 Engines	GMC Drive Axle Data	Spicer 5831 Aux Transmission

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