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Cliff Read’s 1/25-scale 1958 Chevrolet Suburban with factory optional NAPCO four-wheel drive

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Photos courtesy Cliff Read.

[Editor’s Note: Cliff Read, one of the modelmaking brothers who have shown off their scratchbuilding skills here previously, is back with another scale transformation, this one focused on a NAPCO-equipped Suburban. Thanks to Gene Herman for facilitating these stories!]

NAPCO was an auto parts company that manufactured aftermarket four-wheel-drive conversions for various American light trucks, with the first documented completion done on a GM 3/4-ton truck in 1951. Before the introduction of General Motors’s Task-Force Series trucks in 1955, the conversion could only be done on 3/4-ton GM trucks because the previous 1/2-ton trucks had a closed driveline.

“NAPCO” is an acronym for “Northwestern Auto Parts Company” which was located in Minnesota, and before 1957 these four-wheel-drive conversions were done as relatively simple, mostly bolt-on installations. In the case of the General Motors Task Force Series trucks, these were actually offered at first as a dealer-installed option, but in 1957 until 1959, General Motors began offering the NAPCO “Powr-Pak” four-wheel-drive option right on Chevrolet’s assembly line, including for 1/2-ton trucks. General Motors had actually begun offering the same option on their GMC truck assembly line a year earlier.

Unlike today’s light truck market, American trucks manufactured before the late ’60s were, for the most part, strictly commercial vehicles – work trucks.  The four-wheel-drive versions (they were seldom called 4×4 trucks at that time, except in the military) were even more likely to be rough duty work trucks and, with the exception of Jeep vehicles, were often built with considerably more ground clearance than their two-wheel-drive counterparts.

The Chevrolet factory-assembled NAPCO trucks were only available with the 235-cu.-in. six-cylinder engine (GMC trucks did offer a Pontiac-based V-8 as well as their six), and the Suburban versions were available with either a tailgate or the panel-van style split doors. Wheels were six bolt, and could be either 16.5 inches or optional 17.5 inch diameter with a variety of tire options.

An Internet search of NAPCO Chevies will bring up lots of restored pickups and Suburbans with an abundance of chrome trim, accessories and aftermarket wheels/tires, etc. but, as you might imagine,  back in the ’50s, these were serious work trucks used by geologists, contractors, surveyors, civil engineers, etc., and were required to take the abuse of rough terrain. They were usually devoid of deluxe trim options and usually carried the basic painted grill, hubcaps and bumpers as well as the painted outside driver’s rear view mirror. In 1958, the Chevy truck six-cylinder motor was painted a grey color and the wheels on non two-tone trucks were always factory painted in black.

My brother, Larry, and I are constantly on the lookout for toys or abused collector model candidates that can be the starting point for interesting, unusual projects that aren’t available as plastic or resin kits, and this one began from a toy-show purchase of a ’57 Chevy Suburban diecast suffering from paint problems, abuse, and neglect. To add some additional challenge to my project, I decided to convert it into a 1958 version since I had a cheap Motormax ’58 pickup cab left over when I pirated its pickup box for a previous model project. The basic NAPCO front axle, transfer case, and driveshafts came along on a $19 M2 marketed diecast toy GMC pickup, although many modifications would be required for detail and accuracy.

Disassembling some diecast models can be somewhat tricky because many of the plastic detail parts are often fastened in place with really durable glues and adhesives. The windshield was one of the casualties on this particular disassembly, so I was forced to make a new one in polycarbonate, giving me the opportunity to correct the top edge to allow the minor roof overhang that these vehicles should include.

The well proportioned six-cylinder motor came from AMT’s ’60 Chev pickup kit to which I added the appropriate oil-bath air filter, ignition wires, fuel and vacuum lines, as well as heater hoses.

I bought some 1/24 scale off-road rubber tires online and used a sharp Exacto knife to slice a section out of the center of the tread-width, using cyanoacrylate glue to reattach the remaining halves to achieve the narrower look of period mud/snow tires.

The main body paint on my finished model is done in automotive basecoat/clearcoat, mixed to approximate ’58 Chev truck Granite Grey, and smaller details are done in Humbrol, Testors, and Tamiya paints.

The basic Grecian Grey bumpers, hubcaps, and grille color is from Krylon, and the tiny Chevrolet lettering and hubcap bowties are done with a fine-line permanent art marker.

Back in the day, I found the business-like look and added ground-clearance of the rare four-wheel-drive Chevies that I saw to be exceptionally memorable, and building a scale model of one of the NAPCO-optioned Chevies was on my to do list for quite a while.

Before starting on my NAPCO project, I’d collected a fair bunch of reference from brochures as well as Internet searches. I knew that anyone not familiar with these old four-wheel-drive Chevies, would be skeptical of the extreme ride height that my model would portray.

The front body clip was removed from both the original 1/24 scale ’57 Suburban diecast, as well as from a same scale ’58 pickup cab. These were both from the same era of Taskforce Chevy trucks and hopefully, with a little effort, would be interchangeable.

In order to mate the two main diecast body parts durably, the upper fender/cowl areas were drilled to accept some brass wire pins. The lower fender and rocker panel areas were also drilled with a much finer drill to accept a stiff piano wire pin to make the lower mating area durable as well. Epoxy was used as the permanent adhesive for the joints. As expected, there was some bodywork (Bondo) required to blend the minor shape discrepancies.

The original excessive dog-leg door hinges were removed and new tighter hinges were fabricated using stiff wire epoxied to the inner door  that would meet up with a short piece of tubing epoxied to the kick-panel area. I wanted the space between the open doors and the front fenders to more closely approximate the look of the real trucks.

A Google search showed me that the real NAPCO Chevies used a ball-joint style of steering king pin detail and I was able to mimic that detail using wire, aluminum tubing, and a plastic bead. The 4×4 M2 toy that I was using for some of my four-wheel-drive chassis detail (transfer case, front axle center, driveshafts, etc.) used an unrealistic simple toy-like steering detail.

Following the info in my brochure, I fabricated the transfer case shifter bracket on the frame using sheet aluminum and tubing.

All the Chevy assembled NAPCO-optioned light trucks used the Chevy six-cylinder motor and mine was found in an AMT Chevy pickup model kit. I detailed the motor with an external oil filter, plug wires, oil-bath air filter, and fuel line, etc. In ’58 the six-cylinder engines were grey in color and the factory wheels on all non-two-tone trucks were black.

The firewall mounted battery received simulated connections using wire ,small sections of pinched aluminum tubing and straight pins for the terminals.

The ’58 engine hood had to be modified to use the Suburban’s dog-leg hinging arrangement and I also wanted to add simulated scissor hinges as used on the real trucks. A google search found original style hinges which I followed using brass, and styrene.

The windshield was formed in clear polycarbonate with black coated wire formed to simulate the rubber gasket.

The main finished and painted body parts ready for final assembly.

The finished and assembled chassis ready to be fastened to the body.

The finished vehicle. Paint is automotive basecoat/clearcoat.

The finished ’58 NAPCO four-wheel-drive Chevy shown both with an original ‘58 GM brochure as well as beside a Danbury Mint deluxe version of a two-wheel-drive ’57 Suburban.