Napco Four Wheel Drive Vehicles
Encyclopedia
NAPCO was founded in 1918 and based in Minneapolis. During World War II, NAPCO helped the war effort by producing specialized mechanical parts and assemblies that were tested in war conditions.
As early as 1942 NAPCO began building four-wheel drive
assemblies to be fitted to Ford, GMC, Chevrolet and Studebaker vehicles however NAPCO is primarily associated with GMC and Chevrolet pickups. From 1942 to 1956 4x4 GMC and Chevrolet trucks could be ordered by the government and civilians with a NAPCO Power-Pak kit and the kit oculd be installed later. The retail price of Napco Power-Pak was $995. This option raised the price on a new two-wheel drive truck from $1,548.96 to $2,796.96. The kit was shipped in a crate measuring 80"x30"x26" weighing 1,410 pounds. In a matter of 3 hours with as little as 4 holes drilled in existing chassis a truck would be converted into a "Mountain Goat", a "full sized truck that will climb steep inclines with ease". One feature was the "shift on the fly" rubber mounted transfer case
with a dual-range option. There were companies that installed these upgrades for the previously mentioned manufacturers. Besides the four-wheel drive units NAPCO also provided winch
es, auxiliary transmissions, tandem drive axle
s, hydrovac systems, and dump truck
bodies.
From 1956-1959 the NAPCO Power-Pak option could be ordered directly from GM (an official RPO
690 was assigned in 1957) and factory installed on trucks with very few modifications to the original chassis
. The 1955 4x4 NAPCO GMC or Chevrolet was a $1250.00 to $1550.00 optional add on. The 1957 Chevrolet and GMC 3100 4x4 price was a bargain at $2549.00 compared to the earlier add on kits. In 1960 NAPCO and GM parted ways when GM redesigned the front suspension on their 1960 pickup line so that it wasn't easily compatible with the existing Power-Pak kits.
Prior to 1955 NAPCO Power-Pak conversions were done on 3/4 and one ton GMC and Chevrolet chassis. The Pre-1955 1/2 ton chassis used an incompatible "torque tube"
drive. In the fall of 1954 GMC and Chevrolet changed the 1955 1/2 ton pickup and Suburban models to the compatible Hotchkiss drive
.
Today these trucks are still considered to be very versatile and durable 60 years later and are considered to be collectible by NAPCO enthusiasts.
Marmon-Herrington
in Indianapolis. Marmon-Herrington
is commonly associated with equipping 1940s and 1950s Ford trucks with 4 wheel dive.
Dodge Trucks World War II Power Wagon.
Willys Overland Jeeps.
As early as 1942 NAPCO began building four-wheel drive
Four-wheel drive
Four-wheel drive, 4WD, or 4×4 is a four-wheeled vehicle with a drivetrain that allows all four wheels to receive torque from the engine simultaneously...
assemblies to be fitted to Ford, GMC, Chevrolet and Studebaker vehicles however NAPCO is primarily associated with GMC and Chevrolet pickups. From 1942 to 1956 4x4 GMC and Chevrolet trucks could be ordered by the government and civilians with a NAPCO Power-Pak kit and the kit oculd be installed later. The retail price of Napco Power-Pak was $995. This option raised the price on a new two-wheel drive truck from $1,548.96 to $2,796.96. The kit was shipped in a crate measuring 80"x30"x26" weighing 1,410 pounds. In a matter of 3 hours with as little as 4 holes drilled in existing chassis a truck would be converted into a "Mountain Goat", a "full sized truck that will climb steep inclines with ease". One feature was the "shift on the fly" rubber mounted transfer case
Transfer case
A transfer case is a part of a four-wheel-drive system found in four-wheel-drive and all-wheel-drive vehicles. The transfer case is connected to the transmission and also to the front and rear axles by means of drive shafts...
with a dual-range option. There were companies that installed these upgrades for the previously mentioned manufacturers. Besides the four-wheel drive units NAPCO also provided winch
Winch
A winch is a mechanical device that is used to pull in or let out or otherwise adjust the "tension" of a rope or wire rope . In its simplest form it consists of a spool and attached hand crank. In larger forms, winches stand at the heart of machines as diverse as tow trucks, steam shovels and...
es, auxiliary transmissions, tandem drive axle
Axle
An axle is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...
s, hydrovac systems, and dump truck
Dump truck
A dump truck is a truck used for transporting loose material for construction. A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear, the front of which can be lifted up to allow the contents to be deposited on the ground behind the truck at the site of...
bodies.
From 1956-1959 the NAPCO Power-Pak option could be ordered directly from GM (an official RPO
Regular Production Option
A Regular Production Option is a General Motors standard coding for vehicle configuration options. These codes are a combination of 3 alphanumeric characters and refer to a specific option or modification to the vehicle...
690 was assigned in 1957) and factory installed on trucks with very few modifications to the original chassis
Chassis
A chassis consists of an internal framework that supports a man-made object. It is analogous to an animal's skeleton. An example of a chassis is the underpart of a motor vehicle, consisting of the frame with the wheels and machinery.- Vehicles :In the case of vehicles, the term chassis means the...
. The 1955 4x4 NAPCO GMC or Chevrolet was a $1250.00 to $1550.00 optional add on. The 1957 Chevrolet and GMC 3100 4x4 price was a bargain at $2549.00 compared to the earlier add on kits. In 1960 NAPCO and GM parted ways when GM redesigned the front suspension on their 1960 pickup line so that it wasn't easily compatible with the existing Power-Pak kits.
Prior to 1955 NAPCO Power-Pak conversions were done on 3/4 and one ton GMC and Chevrolet chassis. The Pre-1955 1/2 ton chassis used an incompatible "torque tube"
Torque tube
A torque tube system is a driveshaft technology, often used in automobiles with a front engine and rear drive. It is not as widespread as the Hotchkiss drive, but is still occasionally used to this day...
drive. In the fall of 1954 GMC and Chevrolet changed the 1955 1/2 ton pickup and Suburban models to the compatible Hotchkiss drive
Hotchkiss drive
The Hotchkiss drive is a system of power transmission. It was the dominant form of power transmission for front-engine, rear-wheel drive layout cars in the 20th century...
.
Today these trucks are still considered to be very versatile and durable 60 years later and are considered to be collectible by NAPCO enthusiasts.
Other early 4x4 manufacturers
Other early 4x4 pickup and 4x4 conversion kit manufacturers include;Marmon-Herrington
Marmon-Herrington
The Marmon-Herrington Company, Inc. is an American-based manufacturer of axles and transfer cases for trucks and other vehicles. Earlier, the company built military vehicles and some tanks during World War II, and until the late 1950s or early 1960s was a manufacturer of trucks and trolley buses...
in Indianapolis. Marmon-Herrington
Marmon-Herrington
The Marmon-Herrington Company, Inc. is an American-based manufacturer of axles and transfer cases for trucks and other vehicles. Earlier, the company built military vehicles and some tanks during World War II, and until the late 1950s or early 1960s was a manufacturer of trucks and trolley buses...
is commonly associated with equipping 1940s and 1950s Ford trucks with 4 wheel dive.
Dodge Trucks World War II Power Wagon.
Willys Overland Jeeps.