Exclusive Content
Original Shows, Motorsports and Live Events
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit www.motortrend.com for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM

Swapping a 5.9L Cummins into A 1973 to 1991 Suburban

Doomsday Diesel Part 1

David Kennedy
Jan 1, 2012
Photographers: David Kennedy
In 2012, the world isn’t going to end, zombies aren’t going to attack, and there won’t be riots in the streets. But if it does, they do, or there are—we’ll be ready!
Photo 2/15   |   Our Doomsday Diesel buildup began with a ¾-ton GMC Suburban that’s based on the ’73 to ’87 GM pickup. These trucks are caveman simple, all steel, and every part you could need is available from the aftermarket. We found our ’91 with 200,000 miles for $2,400. The first step was to pull the gas engine and sell it on eBay.
In the next 12 issues, we’re going to build a diesel vehicle for maximum survivability in the worst possible scenarios. We’re going to create a simple truck that exploits the versatility, durability, and efficiency diesels offer. The Doomsday Diesel Suburban will be part getaway car and part urban-assault vehicle. It’ll have all-terrain capability, a 1,000-mile fuel range, and enough room to carry a small squad of survivors.
We begin this month by bolting a ’95 5.9L Cummins into a ’91 ¾-ton GMC Suburban. This swap has been done many times, but our plans call for using a GM transmission close to the factory location, removing as little of the frame as possible, and retaining the ’94 to ’98 Cummins fan. To help us with the project, we’ve enlisted Mercenary Offroad in Camarillo, California.
In the months ahead, we’ll plumb, wire, and create an exhaust for our Cummins. We’ll also reinforce the chassis, beef up the drivetrain, and upgrade the interior to keep our Sub on the road for years to come. When we’re done, we’ll have a vehicle that’ll not only be a blast to drive, but one that’ll keep us safe and sound come December 21, 2012—no matter what the Mayan calendar says might happen.
Photo 3/15   |   We chose this bolt-in engine cradle from Screamin’ Seeman Off Road (SSOR) because it uses ’03 to ’07 engine mounts and ties into the frame just as the stock crossmember did. Its C-channel design (arrows) is fully adjustable and only requires the truck to have a 2½-inch suspension lift to prevent oil-pan-to-axle interference. We drilled out four rivets, removed the factory crossmember from the frame, and temporarily mounted the SSOR cradle.


Wheat Ridge, CO 80033
Mercenary Off Road
Sun Valley, CA 91352
TCI Auto
Screamin Seeman Off Road
Faribault, MN 55021