The Cummins swap is feasible. Performance Automotive (www.transmissioncenter.com) should be able to set you up with the proper adapter so you can retain your present transmission. However, if you plan on doing a lot of highway driving, then a transmission with an overdrive may be a better choice. You might just be better off buying an engine that has the overdrive automatic along with a transfer case attached.
It’s going to be a lot of work to make everything fit, especially the intercooler if you go with a turbocharged motor. It’s also going to be expensive. Going to a non-turbo’ed engine may not gain you anything performance-wise. It will not be an inexpensive swap, and you’re taking your chances on finding a good motor. The BT6 engine is noisy, and that means it’s tiring on a long drive unless you plan on lots of floor and underhood insulation.
Yes, looking at websites and forums gets really confusing, as there are lots of different people expressing their opinions, and sometimes they may or may not be providing good information. It takes a bit of effort to weed out the good from the bad.
Before you commit to the Cummins swap you have a couple of other possibilities to think about. One is to keep your present 6.2L and take off all the military 12/24-volt crap and rewire the truck. Gale Banks (www.bankspower.com) makes a turbocharger kit for this engine that makes a real difference in performance. There’s an article on this that you can check out www.fourwheeler.com for more information. It would also be a good idea to take a look at www.thedieselpage.com; it has lots of great info.
Another thought is to forget about the diesel and go with a big-block Chevy (gas) motor. The initial cost will be a lot lower, and power output would be about the same as the diesel swap. Yes, you will not get the fuel mileage, but the swap will be so much simpler. It takes a lot of miles, usually in the range of at least 100,000, to make up the difference in fuel mileage versus overall cost. Remember, oil changes in the diesel will be about double the cost, if not more, of changing the gas motor’s oil, and even fuel filters need to be changed more often and are considerably more expensive. Then there’s fuel cost. Right now in my area, diesel is almost 50 cents more per gallon than gasoline.
As to the 4.56:1 axle ratio, I think that it would be just about perfect for overall performance, both on and off the highway.
Tire clearance at full steering lock? I don’t think that the extra inch of width is a problem. A lot depends on the amount of backspacing the wheel has. You might give the guys at Off Road Design a call (970/945 7777, www.offroaddesign.com) and get their opinion on the proper amount of backspacing for clearance without the tires extending too far out the fenders. While you’re at it, look at their website for information on lift and crossover steering.
Where To Write
Address your correspondence to: Four Wheeler, 831 S. Douglas St., El Segundo, CA 90245. All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department can also be reached through the website at www.fourwheeler.com. Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.