Art Morrison Goes Off-Road

Could This Be the Ultimate 4×4 Chassis?

By Ron Ceridono

Art Morrison has a long history of building performance vehicles. As a teenager he collected a number of trophies with his homebuilt, big-block–powered, straight-axle–equipped ’54 Chevy. Morrison’s passion for performance ultimately led him to open Art Morrison Enterprises (AME) in 1971, which quickly grew into one of the leading drag race chassis and component manufacturers in the country.

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Research and development of the new 4×4 suspension and chassis was carried out on “Brush 101,” a retired fire department pickup.

Ever the innovators, AME grew in size as the company broadened its scope by including components for high-performance street vehicles. That led to the revolutionary direct-replacement chassis for ’55-57 Chevrolets. Introduced in 2002, the all-new suspension design gave these vintage vehicles the best in contemporary ride and handling characteristics. Today AME offers direct-replacement performance chassis for a variety of cars and trucks, custom one-off chassis for virtually any vehicle imaginable, and B-body Mopar K-members with coilover suspension.

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During the testing phase a subframe with three-link front suspension was grafted onto the stock GMC framerails.

After 51 years in business, Morrison decided to step down and turn the reins of AME over to Matt Jones. Jones has been with the company since 2004, serving first in the engineering department, then as operations manager, and now as president. Under Jones’ leadership AME continues to develop new products, the latest being a new 4×4 chassis for ’73-87 Chevrolet/GMC pickups and Blazers with ’67-72 applications to follow.

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The new front axle uses a Strange centersection with the remainder of the components being built in-house at AME.

This new AME 4×4 chassis has been under wraps for some time. The test mule for the development of the suspension and frame was a ’74 GMC 2500 with a 350ci small-block and a four-speed transmission. A retired Mapelton, Utah, fire department truck, “Brush 101,” showed a mere 15,000 miles on the odometer.

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Front suspension includes coilover shocks, a Panhard bar, and hydraulic snubbers (arrow).

The initial development of the suspension was done by adding a 2×4-inch rectangular tube clip to the GMC framerails. The three-link front suspension used a Panhard bar and coilover shocks. During the development process two front axle assemblies were developed, one with 8-lug hubs the other with 6-lug. Both axles use large-diameter, heavy-duty tubes with fabricated ends that mount fabricated steering knuckles with Super Duty hubs. In both cases axles are 35-spline. The major difference between the 6- and 8-lug axles is the centersection—the 6-lug uses an OEM-style 9-inch housing while the 8-lug uses a fabricated 9-inch housing. On production chassis a variety of Currie gearsets and traction devices will be available; in the case of GMC “Brush 101” 5.13:1 gearsets were installed in both ends with ARB air lockers. To match the capabilities of the front suspension, the rear was set up with triangulated four-bars and coilovers. As with the front axles, 6- and 8-lug versions of the rear axle assembly will be offered.

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In the rear the fabricated axle housing includes a back brace. Axles are 35-spline full floaters with super-duty hubs.

With the front and rear suspension thoroughly tested, the AME engineering staff went about designing a new frame. The main rails are fabricated from 2×6-inch rectangular tubing blended into mandrel-bent 2×4 rectangular tubing at each end; frames will be available for short and long wheelbase applications. These new frames are much stronger than the originals, providing a much more stable platform for the long travel suspension. But don’t let the rugged look fool you, this chassis is as at home on the road as it is off of it—and no cutting is required for installation.

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The rear suspension uses triangulated four-bars with coilovers, hydraulic snubbers, and limit straps.

AME broke new ground with the development of replacement automotive chassis that gave owners of vintage vehicles the opportunity to experience the best in contemporary handling characteristics. Now AME is bringing that same level of performance to four-wheel drive fans as well. Think of it as the new ground being broken regardless of whether it’s asphalt or dirt.

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Initial off-road testing proved the new AME suspension was more than capable of handling even the most rugged terrain.
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Satisfied with the suspension’s capabilities, AME designed a new frame that is a direct replacement for the original.
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The tubular transmission and transfer case crossmembers bolt in. The brackets outside the frame are cab mounts, the raised brackets in the rear mount the pickup box.
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A removable brace ties the two coilover towers together (note the attachment bolts). Bracket on the sides of the frame accommodate hydraulic snubbers and the engine mounts are LS.
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Front and rear axle tubes are an extremely stout 3 inches in diameter with 1/4-inch wall thickness.
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Custom-fabricated axle ends accept Dana 60 ball joints and U-joints.
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Like everything from AME, the new 4×4 axle housings are beautifully executed. The large bracket is for the upper three-link locator; other brackets are Panhard bar, coilover, and sway bar.
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Fabricated steering knuckles accept super-duty hubs, as in the rear axles are 35-spline.
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For strength, the draglink and tie-rod ends are in double shear between two steering arms.
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AME’s prototype truck will be equipped with a modified direct-injected L8T engine backed by a 10L90 transmission with an Atlas transfer case.
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Tires on the GMC prototype are Atlas 40×13.50R17LT on-bead lock wheels. Locking hubs are Warn.
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Steering gear for the new chassis is by way of a Dodge heavy-duty six-bolt, 1-ton power steering box.
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For 8-lug applications an additional power steering ram (arrow) attaches to the tie rod.
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Hydraulic bumpstops are used on 8-lug applications; 6-lug suspensions use the foam style.
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A sway bar is part of the front suspension package—it does not have to be disconnected to obtain full suspension articulation.
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The complete 8-lug front suspension is as rugged as it is impressive looking. Note the dip in the Panhard rod for engine clearance.
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Up front suspension compression from ride height is 10 inches—total travel from full compression to full extension is well over 30 inches.
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Brakes on the front axle are six-piston Wilwood calipers with 14-inch rotors.
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As in the front, the rear 8-lug axle uses a Strange centersection while the remainder of the housing is built in-house at AME.
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The rear suspension has the coilovers mounted to the lower arms of the triangulate four-link. This is on the modified stock chassis; the production configuration will be the same.
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In the rear, four-piston Wilwood calipers and electric parking brakes are used.
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With capabilities that are as impressive from the rear as from the front, Jones can justifiably wear a smile of pride in his company’s accomplishment.

Art Morrison Enterprises
(800) 929-7188

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