This Beast Mode 1988 Toyota 4Runner Is A Homebuilt Masterpiece

Mark Welliver of Nescopeck, Pennsylvania, dove into the build of this 1988 Toyota 4Runner with a comprehensive plan. His goal: to make the rig an off-road beast with room for his family. Mark has thirty years of off-road experience, and his wheeling résumé includes Rausch Creek Off-Road Park and the defunct—but legendary—Paragon Adventure Park. We found the rig at the 2025 Summer 4-Wheel Jamboree in Bloomsburg, Pennsylvania.

1988 Toyota 4Runner Stripped To The Frame

Mark purchased the 4Runner in 2009. He immediately discarded the IFS setup and swapped in a solid front axle and leaf-spring suspension. He also replaced the automatic transmission with a five-speed manual. He says, “Eventually, the 3.0-liter got tired, so in 2013 I did a 3.4-liter swap and also installed some used Alcan Spring Orbit-Eye front leaf springs.” Mark wheeled it in this configuration until 2023, when he decided it was time for a refresh.

Mark stripped the SUV down to its frame, which he reinforced with steel plates—4Wheel Underground plates up front and custom plates in the rear. The outcome is a stout foundation for the tough and functional rig.

Dual Transfer Cases And More

The 3.4-liter V6 engine was pirated from a 2000 4Runner. Mark says it bolted in with minimal mods, which included wiring and a 2.5-inch-diameter exhaust with a Magnaflow muffler. Bolted to the Toyota R150F five-speed manual transmission is a Marlin Ultimate Crawler setup that uses a pair of Toyota RF1A transfer cases.

Salvage Yard-Sourced Differentials

Mark fitted the 4Runner with Trail-Gear Rock Assault axle housings. The front features a salvage yard–sourced, 80-series Land Cruiser–application 8-inch high-pinion differential with an electronic locker, along with Six Shooter knuckles and RCV 30-spline chromoly axleshafts and Birfields. Out back, the housing is equipped with an 8-inch differential with an electronic locker, also sourced from a salvage yard—specifically, a 2001 Tacoma TRD. Its axleshafts are from a 1988 4Runner. Axle gearing is 4.88:1.

Remote-Reservoir Coilovers, Increased Wheelbase

The 4Runner’s suspension is a three-link setup with 14-inch-travel Radflo 2.0 remote-reservoir coilovers. The coilovers feature custom shock valving and coil spring rates. Up front, Mark installed 4Wheel Underground three-link suspension brackets, but he made the link bars himself. The lower links are made from 2-inch-diameter solid aluminum, while the uppers are constructed from 1.75-inch-diameter, 0.120-inch-wall material. Each link bar is fitted with Ballistic Fabrication Ballistic Links.

Additionally, the rear suspension includes Barnes 4WD shock towers frenched into the 4Runner’s frame. Other suspension mods include 4Wheel Underground limit straps, Radflo bump stops up front, and Carbon Shock Technologies bump stops in back. The rig rolls on 37×12.50R17 BFGoodrich Krawler T/A KX Blue Label tires mounted on 9-inch-wide Pro Comp Trilogy aluminum beadlock wheels.

Mark increased the rig’s wheelbase by relocating the front axle forward three inches and the rear axle rearward one inch.

Bobbed And Protected

Mark increased the 4Runner’s departure angle by bobbing the tail end of the SUV by 11 inches. Consequently, it was necessary to modify the rig’s hardtop to fit. To do this, he made cuts at the sliding windows of the top.

Other exterior modifications include a homebuilt front bumper based on a Trail-Gear winch mount. There’s also a custom rear bumper, a Badland 12,000-pound-capacity winch, and a pair of custom rock sliders.

Rollcage, Four-Point Harnesses

Inside, Mark installed a 4x Innovations roll cage, modified with additional tubing in the rear to include a safety harness bar for rear seat passengers. The factory seatbelts were upgraded to Aces Racing four-point harnesses.