Stacks Against You
Q I need to relocate my gas tank to accommodate some 3-inch stacks we are putting up through the back. What is the ideal way to do this without putting a fuel cell in the bed? I want to mount a bench seat back there.
A From your photo I assume you are building a Dodge half-ton and want dual stacks. I would look into a Ramcharger fuel tank that mounts behind the rear axle to replace your factory tank. Another option is to build a platform 5 or 6 inches high in the bed and run the exhaust under the platform from the passenger side so you can have dual stacks. You could then mount the bench seat onto the platform.
Nuts, I’m Confused
Q I have a ’91 3⁄4-ton Chevy truck that I’d like to build for mud bogging. I want something that works in the slop but that can also be driven on the street. I have a small car as well, so fuel economy isn’t that important from the truck. I want big tires, a big engine, and something I can hammer on off-road, especially in the mud. I recently found a deal on an 8.1L big-block from a late-model Suburban. I’ve also purchased a Ford front Dana 60 since I know the IFS has to go. Will the 8.1L work in place of my tired old TBI 454? What other upgrades do you recommend for a mud machine?
A Trucks need big power to spin big tires in the deep mud, and the 8.1L is an unsung hero in my view. A lot of people overlook them in favor of the lighter GM LS engines. It should bolt right up to your current transmission without too much drama. You probably have an 4L80 transmission behind the 454, and most of the 8.1Ls also came in front of that transmission. There were different styles of 4L80 automatics, so it depends on whether you are running the engine computer that will run the transmission or not. If so, you may need a similar-era transmission. I would go with a manual valvebody in the automatic so you can shift and choose gears accordingly; this gives you some great control. An outfit in New York, CK Performance (www.ckperformance.com), offers full manual valvebodies for these transmissions. Also, contact Pacific Fabrication (www.pacificfab.net), which has done a few custom wiring harnesses and 8.1L swaps.
For tires and suspension I would run rear leaf springs and a coil-link front suspension or leaf spring up front for your solid-axle suspension. To get big tires—say, 44-inch Boggers (Boggers are hard to beat in the mud)—I would recommend pushing the front axle slightly forward when you swap it in. This will help keep the tires out of the fenders near the front doors. You’ll want some serious lift, but I’d also trim those fenders so the tires clear at full suspension compression. If your truck came with the full-floating eight-lug Corporate 14-bolt, then you should be fine for tires up to 44. I’d look into low gears. Yukon Gear & Axle (www.yukongear.com) offers 5.38 gears for the 14-bolt, and many gear companies have that ratio for the high-pinion 60.
Building a mud truck that can still be street driven isn’t easy, but I think you’re on a good track. Every state in the nation has mud, so I feel your question is pertinent to all the readers. I’d like to give your letter this month’s Nuts, I’m Confused award. BDS Suspension (www.bds-suspension.com) will supply a traction bar kit for your truck. When you go to big power, low gearing, and huge tires, you’re very likely to see some axlewrap in your rearend, especially with a spring-over suspension. These traction bars are 1⁄8-inch-wall with large polyurethane bushings and designed to fight axlewrap. In the worst case scenario, pinion wrap can change pinion angle and cause the driveshaft joints to bind and break. Although BDS doesn’t offer a bar specifically for your 3⁄4-ton, the company’s half-ton bars should work on the frame end and may need slight modification to work on the 14-bolt. BDS offers suspension lifts for a large variety of 4x4s, from Jeeps to fullsize trucks.
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