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Cost of a Cummins Swap

A Beginner’s Guide To What’s Really Involved In The Conversion Of Your Dreams

Whether it’s a Super Duty that’s being converted, a sled puller, a drag racer, an off-road vehicle, a rat-rod, or virtually any kind of daily driver, Cummins is king when it comes to engine swaps in the diesel world. But while a Cummins swap is the obvious and common choice for most builds, that doesn’t necessarily mean it will be cheap to pull off, or easy to perform. Measurements, locating a donor vehicle, and sourcing an engine are one thing, but actually dropping it into place and making it run and function can be a whole other story. Oftentimes, transmission selection, electronic integration, and the miscellaneous parts that are required to make the swap drivable consume the most time.

Then comes the custom components or solutions that can’t be bought but have to be made. If you’re not adept at fabricating, costs can skyrocket by enlisting the help of a professional. Being realistic with your own wrenching, welding, and electrical knowledge goes a long way in determining if you’re going the DIY route or having an independent shop handle the bulk of the work (if not all of it). In the following pages, we’ll run through a host of common engine and transmission combinations. Our aim is to highlight the unrealized, unexpected costs that can come up during the course of a Cummins swap—as well as give you an idea of what it will cost to have a professional perform the job for you.

Ford Super Duty Manual Shift
In the wide world of Cummins swaps, it doesn’t get any more economical than dropping a 12-valve into a Ford Super Duty that was originally equipped with a manual transmission, such as the ZF-6. With a throttle cable, transmission adapter plate and the appropriate flywheel and clutch combination, you’re essentially ready to roll after hooking up the starter. Depending on how you go about your parts sourcing, on a homemade project this type of swap can cost you a few thousand. For a clean, well-executed job performed at a reputable shop, you’ll likely be looking at a $7,000 to $9,000 bill.
Ford Super Duty 5R110W TorqShift
The 5R110W TorqShift employed in Super Duty’s from ’03-’10 is known for its durability behind either the 6.0L or 6.4L Power Stroke. However, if you plan to keep Ford’s five-speed automatic, at the very least a converter change will be required. Even in a mild horsepower application, a different stall speed (and potentially a much stronger) converter is mandatory to both harness and utilize the Cummins’ abundance of low-end torque.
Cummins with Ford 5R110W TorqShift
Going the 12-valve, 5R110 route can be pulled off for $12,000 to $15,000 at a shop that’s seasoned in Cummins swaps. Sprinkle in a little more power and the cost obviously goes up, but for a basic, 350hp (ish) 5.9L-powered ’03-’10 Super Duty you’ll get a Cummins repower that’s cleanly done and rock-solid reliable.
TCM-2800 Powertrain Control Solutions
Getting the 5R110 to play well with a 12-valve in front of it calls for a stand-alone transmission controller, not the Ford PCM. The most popular controller here is the TCM-2800 from Powertrain Control Solutions (PCS). The company’s TCM-2800 allows for fully programmable shift points, shift firmness, and control over torque converter lockup. You’re also given a base calibration to work with, along with sound technical support from the company itself. A TCM-2800 can easily be built into the aforementioned $12,000 to $15,000 swap cost if the conversion is being performed by a professional shop.
6.7L Cummins Diesel
Whether you’re performing the swap yourself or relying on someone else, you’ll spend considerably more coin on a common-rail Cummins swap. For Ford-Cummins conversions, even retaining the 5R110 transmission will still call for a $20,000 to $25,000 budget if you’re enlisting a veteran swap shop’s help—and that’s a basic setup, though done cleanly and correctly. As with a 12-valve swap, added go-fast parts will add to the overall cost.
4BT Cummins engine
If space under the hood is a major concern, it’s hard to beat the packaging size of a 4BT. One of the biggest advantages of the 6BT’s little brother is that its shorter, 30-inch overall length leaves plenty of room for an engine fan. The 4BT Cummins remains a popular swap candidate for this very reason—along with the fact that virtually any transmission can be bolted up to it with the right adapter plate and appropriate flex plate or flywheel/clutch in the mix.
Electric fan, shroud, radiator package
Given the choice between a mechanical clutch fan and an electric one, the former is the preferred means of engine cooling in any swap project that’s intended to be a tow vehicle. However, in applications where space doesn’t permit the use of a mechanical clutch fan arrangement, electric fans with a proper shroud and radiator package can be made to work effectively.
Cummins fan hub adapter
This simple Cummins fan hub adapter (made by GOS Performance and available through Strictly Diesel) is the solution to all of the engine fan problems encountered in common-rail Fummins projects. Instead of relying on the electronic engine fan employed on Cummins engines, which can struggle to cool adequately, the adapter allows for the use of a Ford mechanical clutch fan. Specifically, combining the mechanical fan clutch from the ’94.5-’97 7.3L Power Stroke with the 23.25-inch diameter fan off of the 6.0L Power Stroke tends to work best.
Due to its lack of emissions controls (and thanks to its immense power potential), the 5.9L common-rail remains a popular engine swap candidate, across the nation. Right beside it in popularity? The 48RE four-speed. Even in 6.7L applications, the 48RE is often chosen over a built 68RFE or an Allison. This is because the 48RE can be made extremely durable with the right parts, parts for it are readily available, and it’s not stupid expensive to prep one for handling additional power.
Considered the holy grail by some, the common-rail Cummins/Allison transmission combo is the ultimate budget blower. First and foremost, the Cummins and Allison can’t talk to each other without help, which also means you get no torque management—and in Ford trucks neither the Cummins nor the Allison will communicate with the Ford electronics. Granted, this can be solved, but there is a reason this is the most expensive combination to run. If you’re dead-set on a common-rail Cummins/Allison powertrain and are having a shop handle your swap, be prepared to spend at least $30,000. The six-speed Allison 1000 controller kit from DeStroked is shown here, which includes the TCM, XFC, and wiring harness you’ll need to integrate an Allison behind any Cummins (or even any engine) you choose.
Then there is the added cost of building the Allison… Unless you’re sticking with a 350hp Cummins, the A1000 won’t tolerate the kind of low-end torque even a mildly powerful 5.9L or 6.7L Cummins can dish out. And, like any other automatic transmission in the diesel industry, the Allison isn’t cheap to reinforce.
Custom-made parts can bring a conversion project to a standstill if you can’t fabricate or wire on your own, but depending on the vehicle you’ve chosen for your swap it can be 100-percent necessary. Especially when you’re out of space under the hood, things like a custom-sized radiator, intercooler (or even water to air unit), expansion tank, or even a compact air cleaner setup may be unavoidable.
Depending on how you compile all the parts required to pull off your particular Cummins swap, it may seem like there are a thousand odds and ends to hunt down throughout the process. For instance, if your 12-valve came out of an old medium-duty application, you may have to source a different water inlet manifold and thermostat housing, or have to change the alternator’s location.
’03-’04 Dodge Cummins throttle bell crank
As another example of how little things can add up in a Cummins swap, many find that an ’03-’04 throttle bell crank is required to swap their later 5.9L common-rail into place. The only problem is that they aren’t cheap, starting at roughly $250 for a used one ($600 or more new)—and then you need the throttle cable as well…
Diesel Conversion Specialists pedal bracket kit with adjustable pedal
Even on 12-valve into Ford swaps, things aren’t always cut and dry. Short of buying an install kit, you’ll have to find a way to make the Ford pedal accept the Cummins’ throttle cable. Diesel Conversion Specialists offers a pedal bracket kit with an adjustable pedal to solve this very thing on ’05-’10 Fords.
Whether you’re up to the task of wiring your Cummins swap or not, it has to be done. Modifying (or blending, as it’s often referred) the engine harness is a good idea in every scenario, 12-valve, 24-valve, or common-rail, to make the engine’s integration as complete as possible. Even sending off the wiring harness for a mechanical, 12-valve Cummins that’s been dropped into a Ford is worthwhile as it can ensure the gauges in the cluster work flawlessly. Both DeStroked Colorado and Diesel Conversion Specialists offer these types of blending services, and they are beyond worth the cost.
’06-’07 model year electronic components such as the ECM, TIPM, engine harness
Adding better electronics to early common-rail engines can be a big help. Swap enthusiasts using ’03 and ’04 5.9L’s for their conversions can utilize ’06-’07 model year electronic components such as the ECM, TIPM, engine harness, and even injectors to allow for true drive-by-wire capability and better engine tuning and performance options. Upgrading to later style electronics is also ideal when an early 5.9L common-rail is purchased without any electronics.
2500 Dodge Ram Cummins truck
Some of the best advice you can get when it comes to Cummins swaps is to find a complete donor truck. Anyone who’s serious about performing a Cummins conversion gets things started with a donor truck, be it a wrecked Ram with parts to pick from, a retired work truck, or a barn find. Not only can you come up with your own engine this way, but you may have a transmission, axles, transfer case, and wiring at your disposal, too.
shift on the fly switch
The bottom line on any Cummins swap is that you have to be resourceful. Trust us, even though there are great conversion kits available in the aftermarket, you’re still going to have to hunt down parts. And if you decide on an electronically controlled engine, the work continues long after you’re done wrenching. For most do-it-yourselfers, getting a common-rail Cummins fine-tuned to the point where it runs, works, and drives flawlessly is the hardest part.
first gen 12 valve Dodge Cummins engine
For utmost reliability, it’s virtually impossible to beat keeping things simple. By that we mean stick with a 12-valve swap and a manual transmission, especially if you’re a newcomer to the Cummins conversion game. Trust us, the common-rail Cummins/Allison transmission combo in a Ford Super Duty does (and always will) be appealing, but you may fight inevitable and intermittent issues (big and small) for some time. However, if you do travel that path, make sure you pick the brains of experts that know exactly how to execute that type of swap, such as DeStroked Colorado or Diesel Conversions Specialists.
12 valve cummins diesel, OBS Chevy truck
Before you commit to anything (be it with yourself or a shop), do your own research. See what’s been done before and don’t try to reinvent the wheel. If you are going to have a shop handle the swap, run your desired truck, engine, transmission, and horsepower plans by them before you start rounding up parts. Seek their advice on what would best suit your needs. Last but not least, make sure they’ve performed Cummins swaps in the past. The last thing you want is a shop that’s learning as they go or outsourcing much of the work.
custom 12 valve Cummins p-pumped engine
Once you’ve committed to the vehicle application, engine, and transmission of your choice, start measuring. Pay special attention to motor mount and accessory drive locations. For example: on OBS Ford trucks the common-rail Cummins doesn’t fit well due to the power steering pump being pulley driven, which protrudes down and causes interference with the  power steering box on the frame. In contrast, the power steering pumps on the 12-valve and 24-valve engines are gear driven (courtesy of the front gear train) and are much more clearance-friendly.
Cummins engine block
No matter which Cummins you choose, start fresh. Installing a take-out engine and assuming it will run forever can lead to downtime and more costs sooner rather than later. A hurt cylinder, warped head, bad injector, or broken piston cooling nozzle might not be information the engine seller will offer up when you buy the engine, so it behooves you to begin anew. Even a reseal will give you an internal glimpse of the engine’s overall health.
tear down of a transmission
The same goes for the transmission you pick to live behind the Cummins. Regardless of its apparent condition, don’t take a chance. Have it torn down and looked over. If you’re adding power to the Cummins this is the time to upgrade the transmission anyway. By rebuilding or reinforcing the transmission now you’re money ahead of a take-out unit that could potentially self-destruct and take everything out with it.

 

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