TECHLINE
COMPILED BY VERNE SIMONS EDITOR@FOURWHEELER.COM PHOTOS: VERNE SIMONS, DIESEL POWER PRODUCTS, ROB BONNEY FABRICATION, AND FOUR WHEELER ARCHIVES
CHEVY SQUARE BODY CUMMINS SWAP I’ve been a fan of the magazine for as long as I can remember. When I was a kid, at the store with my mom I used to grab any and all off-road magazines off the shelf and read them. You can only spend so much time looking at potato salad with your mom. Often, I came home with several of the magazines back when there were a ton. I’m sad that most of those magazines are gone, but I’m glad that Four Wheeler is still here. I’ve never written in with a question but thought I would today. I’m contemplating building a new (to me) tow vehicle although this is still all hypothetical. Something that I can use to tow my trailer with off-road toys or a camper that won’t break a sweat with a load behind it, and something that I can take down sandy backroads or to the campsite without worrying about getting stuck. I’d really like something that can tow about 10,000 pounds or a bit more with a crew cab for space. I really love the Cummins engines (the 12and 24-valve 6BT engines) but finding one of those old Dodge trucks that has any life left is hard these days, and the crew cab trucks are expensive or pretty rough. I also like the style of the old GM square body trucks and think that might be the best place to start since they seem to exist as Crew Cab trucks for sale locally with some regularity. So, I think I’d like to build a Cummins-swapped square body Crew Cab but have a few questions. First, am I stuck finding a used Cummins or can a crate engine be sourced from somewhere? Secondly, what’s the best transmission to use? What about the transfer case? Do I need to find a 4x4 Crew Cab square body to start with, or can I start with a 2WD Crew Cab and convert it to 4x4? Do I need to box the frame? Any insight or ideas would certainly help. MARK VIA EMAIL
WHERE TO WRITE Have a 4x4 tech question you want answered in Techline? Drop an email to editor@fourwheeler.com or message us through our Facebook page at facebook.com/fourwheelermag. All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.
78 MARCH 2022 FOUR WHEELER
You’re not alone in being sad at the loss of most of the many awesome off-road magazines, and you are also not alone when it comes to wanting to build a Cummins-powered square body 4x4. On both topics we agree. We can’t help bring back the other magazines but will keep working hard to make Four Wheeler the best it can be. In regards to a Cummins-swapped square body Chevy, others have had the same idea, making the task a bit easier for you. In the end, it’s hard to deny the classic styling of the square bodies and they are plentiful, which means there are many great sources for parts and more. In order to make this project happen you will either have to be good at fabrication and at finding a deal on good used parts, or you’ll need to have some deep pockets to fund the build, as the price of the components can add up quickly. To answer your question about sourcing an engine, our buddy Cooper at Diesel Power Products tells us there are a few new and several remanufactured crate Cummins 6BTs available in the aftermarket. You can spend what you want on a new or remanufactured engine at a place like dieselpowerproducts.com or start the hunt for good used parts. You can choose the Cummins diesel best-suited to your needs—12valve, 24-valve, Common Rail, or 6.7-liter—but be warned, we have heard some pretty sad tales about folks buying junk used diesel engines. For transmission choices you have a couple of decent options, but in the end, you should select based on what route you want to take and what you want your truck to do. If you can source a used engine locally, it may even come with fourwheeler.com
