Ultimate Off-Road Diesel
The unpaved world can be a cruel place for street vehicles. Mud, dirt, rocks, and snow are not always conquered with horsepower and torque. Often, they are survived by trucks built with simple heavy-duty components. In the off-road world, traction is more important than dyno numbers, and strength comes from using proven components that won't break--even when you pound on them.
To get the most performance off-road, we'd begin with an older truck so we wouldn't cringe every time we scratched it. The solid axle '82-'91 Chevrolet and GMC K30 1-ton pickups make perfect platforms for off-road vehicles because they were built with some of the burliest drivetrain components ever offered. Though their optional 6.2L engines weren't powerhouses, we're not going to suggest swapping the engine out right away because their high compression ratio gives these engines better throttle response than modern diesels. Instead, we'd upsize it with a later-model 6.5L long-block for more power.
Truck: '82-'91 GM K30 ('84-'86 military CUCV preferred)
Engine: 6.5L
Performance modifications: Banks Sidewinder turbo system
Estimated HP: 220 hp
Transmission: TH400 three-speed automatic
Transfer case: Offroad Design Doubler with JB Conversions LoMax 205
Front axle: Dana 60, ARB Air Locker, 5.13 gears, 35-spline chromoly axleshafts, Dynatrac differential cover
Rear Axle: 14-Bolt, Detroit Locker, 5.13 gears, Dynatrac differential cover
Suspension: Offroad Design 6-inch lift front and rear system
Tires: 42x14.50R17 BFGoodrich Mud-Terrain T/A KM2
Wheels: 17x8.5-inch Hutchinson Rock Monster beadlocks
Chassis modifications: Offroad Design steering box brace and High Steer crossover steering kit, PSC ram-assist steering box with hydraulic ram
Body Modifications: Offroad Design tubular front winch bumper and Offroad Design 1-inch body lift, substantial fender trimming for tire clearance
Why it will work: Bulletproof drivetrain components providing optimum traction, simple 6.5L engine, purpose-built