Tossing a heavy Chevy over dunes and plowing through the sand is a blast. That's exactly what Rick Humphrey was doing when we spied his bright orange K5 at the Silver Lake Dunes near Mears, Michigan, but the truck looked as though it would be just as happy slopping through the mud. Rick told us that he hates cleaning the undercarriage, though, so the truck spends most of its four-wheeling life on the dunes.
Did you know that sand actually cleans your undercarriage as you drive through it? It's not good for parts such as bearings or brakes, but driving on sand dunes is like low-pressure sandblasting and keeps everything pretty clean under your truck. That made it easy to spot the upgrades Rick had performed on his Blazer.
Rick says that he built the truck just to have fun with. That doesn't require a ton of modifications if you start with a good truck as he did. By keeping the tire size moderate, Rick makes the truck work with a mild lift, and he doesn't have to fear breaking an axle. The same goes for the drivetrain: He made only conservative upgrades to the very solid package that Chevrolet put together when the truck rolled off the assembly line.
Then there are appearance mods. Once again, it's hard to improve on the factory's effort. Rick added a soft top, chrome wheels, and Interco Super Swamper TSLs and let the classic body and chrome carry the rest of the vehicle's looks. We like it: Keep it simple but make it work.
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Early K5 Blazers have a look that's hard to beat, and Rick Humphrey's '70 sports a clean body with a combination of aftermarket upgrades that make the truck look and function even better than stock. The soft top tames the sun on the dunes and keeps the sand from inundating the interior. The rear is the stock 12-bolt, which is plenty strong for this application. |
The front-axle assembly is the stock Dana 44. Rick found that the dunes can yank on the steering wheel fairly hard, so he added dual Black Diamond steering stabilizers to keep the wheel steady. |
The interior is beautiful with the stock bucket seats and console, each re-covered with cloth and vinyl. The dash sports a new pad and the same brilliant orange paint that graces the K5's exterior. The original instructions for operating the NP205 transfer case are still intact on the glovebox door. |
The mill is a mild 350 that sports an Edelbrock cam and intake. Rick installed a Quadrajet carb to feed the cylinders, and exhaust manifolds that connect to a dual exhaust system. |
The wraparound bumpers move around a bit when you're blasting through the sand (and even more when the chassis is tweaked during rockcrawling). To keep the bumper from damaging the body, Rick slid automotive interior edging over the top ends of the bumper. Cool idea! |
To lift the front, Rick had the stock springs re-arched. This typically changes the ride characteristics, but it avoids unsafe lift blocks and costly new springs. In addition, all the stock hardware can be retained by having the stock springs re-arched. Rick added Black Diamond shocks at all four corners to better control the axlehousings. |
While not a really common option on early trucks like Rick's, power steering is almost a must on a four-wheel drive. |
The distinctive grille sets the '70 apart from the '71-'72 K5s, which had an uninterrupted egg-crate grille. The '69 and '70 Blazers shared a grille design, but '70 was the first model year this body style was offered with four-wheel drive. |
To lift the rear and keep axlehop (also called wheelhop) under control, Rick used traction-lift bars. These are bars that bolt between the axlehousing and the springs and then continue 12 to 20 inches toward the front of the vehicle. At the end of each bar, there is a bracket that extends upward and sandwiches the leaf-spring pack. Axlehop is caused when the axlehousing tries to rotate as a reaction to the power being delivered through the axles to the tires. The pinion tries to rise in the chassis, but the springs fight this. Also, the U-joint will try to make the pinion line up with the driveshaft. The more the axlehousing rotates, the more violent the hop. Traction-lift bars have adjustable crossbars that allow you to limit the amount that the axlehousing can rotate. If the pinion rises too much, the lower crossbar contacts the spring and stops the axlehousing rotation. The upper crossbar keeps the pinion from falling too much. While these do diminish--and in some cases cure--wheelhop, they also limit suspension travel. For a dune runner like Rick's Blazer, that's not a problem, but the bars probably aren't the best solution for a rockcrawling truck that suffers from wheelhop. |