1955 GMC Pick-upNapco four wheel driveGM 400 small block V-8700-R4 Automatic Transmission373 rear gearsRemaining specifications and NAPCO HISTORY in the article below and YOUTUBE videohttps://www.youtube.com/watch?v=b3R93ZNtQwMOne of the 1st prototypes with very rare differential gear box on the drivers side.Contact me with any questions or to schedule an appointment to see in person. Regards Michael (203) 943-4125You know a couple's love for one another is sincere when a husband goes as far as building this rare and cherry classic '55 GMC NAPCO 4x4 pickup for his wife. Most will express their love with a bouquet ofAfter the GMC was rolled off the trailer, t was disassembled all the way down to the frame; it too was stripped down to bare metal. The frame was then powdercoated satin black by the team at A Plus Coatings inColumbiana, hio. The NAPCO 4x4 "Shift On The Fly" Powr-Pak suspension was refurbished stock with both front and rear axle differentials, rivelines, niversal joints, rum brakes, acking plates, nd shiftlinkage. Leaf springs (both front and rear) are dampened by Rancho shock absorbers. A set of 16x12.50-inch Eagle polished aluminum wheels are wrapped with 33/12.50-16 General Grabber ST rubber.A '78 Chevrolet 400ci engine was disassembled; the block was magnafluxed and machined by Tub Tushine in Leetonia, hio. Tub installed a set of J&E flat-top pistons and Crower I-beam connecting rods andCrower crankshaft. The Vortec cylinder heads are complete with stainless valves, oller rockers, nd heavy duty springs. A pair of Sanderson ceramic-coated headers were bolted up to the Vortec cylinder heads;2-1/2-inch diameter exhausts flow into a pair of Flowmaster mufflers. Following the engine dyno break-in period, couple of power pulls were made, roducing 426 horsepower and 560 lb-ft of torque! After thecrew at Rossler's transmission modified the valve body, ropped in some beefed up clutches and other performance internal components, he 700-R4 transmission was bolted up behind the healthy 400ci block.The rearend was refurbished with new axle and pinion bearings, hen stuffed with a set of Richmond 3.73 gears.The all-steel GMC NAPCO cab, enders, ood, nd bed were fairly straight. It was delivered to Joe, n ol' schoolmate of John's, ho is a full-time painter for a Dodge dealership in Leetonia, hio. Heoccasionallytakes on custom body and paint side jobs. Joe straightened, hen filled and sanded until every wrinkle and imperfection was removed. It was then colored with PPG Viper Red and color sanded between coatsbefore the final multiple clear coats were applied. It was then cut, uffed, nd polished until the deep mirror finish appeared. A beautifully crafted Pros-Pick cedar wood bed floor is separated with stainless steelstringers.bench seat and matching door and kick panels. The simple interior is timeless. An ididit tilt steering column is capped with a white leather-wrapped LeCarra steering wheel. Whiteface Classic Instruments fill thesix-gauge cluster on the dash.An Alpine CD head unit and 600-watt amp produce ample vibes through the two 6-1/2-inch diameter Alpine speakers. Ron Garrod Upholstery is responsible for the flawless retro red/white leather tuck 'n' rollIt seems Chris and John's '55 GMC NAPCO is an award magnet wherever it's displayed. The opportunity to feature this rare old Detroit iron and unique Minneapolis engineered drivetrain is a compliment toTruckin' magazine.Napco HistoryAt first glance this viper red '55 GMC pickup appears to be an aftermarket, ifted 4x4. But if you look closer you will notice the NAPCO badging on the fender. What is NAPCO? It stands for Northwestern AutoParts Company. During the mid-'50s NAPCO started producing their Powr-Pak 4x4 conversion kits for OEM GMC and Chevrolet. Later, he Powr-Pak 4x4 kits were available for Ford and Studebaker trucks.During the WWII years many automotive part companies focused their attention on projects commissioned by the United States government. During this time of war the parts and assemblies were tested on thelargest proving ground on the planet, nder extreme conditions. After the war, overnment priorities changed and NAPCO redirected its vast engineering and manufacturing experience to produce goods forprivate industry, hich included the production of the famous NAPCO Powr-Pak 4x4 conversion.There is some mention that NAPCO started producing 4x4 conversions for GM trucks as early as 1949. But it was not until October 28, 954, hat Chevrolet introduced the '55 1st Series. All of the NAPCOconversions were done on 3/4-ton and larger trucks. GMC and Chevrolet were the most popular conversions. (Later the NAPCO conversions were available for Ford, tudebaker, nd other manufacturers.)During 1955 NAPCO was very busy pushing its proven 4x4 conversion kits on truck upfitters and some of their GMC dealers across the country. That's why this '55 GMC is rare. Upfitters were companies thatinstalled upgrades and accessories like winches, uxiliary transmissions, andem drive axles, ump beds, nd hydrovac systems on stock factory trucks. These NAPCO-enhanced vehicles were branded with the name "Mountain Goat" expressing their climbing abilities.The NAPCO Powr-Pak 4x4 conversion kits were not available for GMC until 1956, hen followed with Chevrolet in '57. By the end of 1957, oth GMC and Chevrolet trucks could be ordered from the factory withthe NAPCO Powr-Pak conversion. The two offered identical systems, ther than the availability of a V-8 and an automatic transmission on the GMC trucks. The Chevrolet could only be ordered with the 235ci six-cylinder and a four-speed manual transmission.The first "All GM" factory 4x4s were introduced in 1960 when both Chevrolet and GMC went to a totally new chassis. NAPCO and its Powr-Pak conversion were left out of the equation due to the introduction ofGM's completely redesigned truck line featuring independent front suspension on the two-wheel-drive trucks and a four-wheel-drive specific chassis on the four-wheel-drive trucks. This was the beginning of theend for the 4x4 Powr-Pak conversion element of NAPCO. NAPCO did produce conversion kits for a few more years, ut the main business shifted to the heavier trucks (1-1/2 ton and larger).After a major loss of the contracts with GMC and Chevrolet to supply conversion packages, APCO sold the rights to the Powr-Pak package to the DANA Corporation in 1961. It seems that since NAPCO wasbought by DANA Corp it was pulled into its black hole during the merger or buyout of SPICER. Who knows?Read more:http://www.trucktrend.com/cool-trucks/0605tr-1955-gmc-napco/#ixzz3eCHZ7uvv