1980-1997 Ford F-250+

Posted by Diesel Conversion on Oct 15th 2020

General information for all F-250, F-350, and F-Super Duty:

You will need to cut holes on your radiator support and also trim the back of your 80-91 grille to allow the intercooler to be installed. Some adjustment on your firewall and passenger side toe board with a large hammer to make some more room for the valve covers and exhaust is also necessary. This is explained in greater detail in our installation manual.

Diesel radiators are recommended for extra cooling capacity if your truck currently has a gas engine. Radiators that have X braces in between the radiator and the engine or any that are wider than 31” don’t work well in the conversion. You may consider swapping in a 96-97 Power Stroke ® radiator with the remote fill tank. These radiators have the hose connections on the same side as the Dodge ® radiators making them easier to connect to the Cummins ® engine. Diesel and Gas truck radiator supports are different so if you plan to change radiators plan to change the core support as well. If you have a 92-97 style Ford use the radiator and core support from a 92-97 Ford ® that had 7.3 Power Stroke or non- Power Stroke diesel (with a 31” wide radiator). If you have an 80-92 style Ford, use the radiator and core support that held a 31” wide radiator from an 84-92 Ford with a 6.9 or 7.3 diesel if you don’t have it already. If you have a 91-93 Dodge radiator and intercooler, they have been used before by fabricating mounting brackets.

Usually the 12 or 24 valve Cummins is the engine chosen for the new power plant in these trucks. A few guys have installed a 03 or newer common rail engine. These require a bit more work because the power steering reservoir on the Cummins will hit the steering box and the ECM must be relocated for engine mounting. The 03 Dodge radiator and intercooler fit & work well in this era of Ford truck.

Generally, gear ratios that are lower (numerically higher) than 4:10 are too low for the Cummins engine. This is detrimental if you don’t have an overdrive transmission. Your top speed and fuel consumption will be less than ideal.

If you would like to have us do the wiring for you, we do offer you modification services for your original Ford engine wire harness.

Check out our Cummins Engine Information article for lots of good information on the Cummins engines as they pertain to conversions!

Transmission information


C-6: Lack an overdrive and a locking torque converter.  Your power transfer, top speed and fuel economy will suffer greatly.  DCS does not recommend using this transmission under any circumstances.

E40D (also 99-02 7.3 4R100) - Unless it’s a Bronco or a F-150, this is what your truck has now if it is a 4 speed automatic. If you are planning on doing constant heavy pulling or adding a lot of performance upgrades to your Cummins you may want to have your transmission rebuilt with aftermarket parts.

When using a 7.3L diesel E4OD/4R100 you'll need a Ford 6.0 diesel starter, which does not require any grinding of the transmission (12 or 24 valve engines only at this time). This adapter plate uses the stock Dodge Cummins flexplate and a torque converter adapter. The plate has to be tilted just 2 ½ degrees to accommodate the starter without any grinding to the transmission or starter.

We offer two styles of transmission controllers for these transmissions- Please refer to the Automatic Transmission Controller article for more information.

The 99-02 7.3 4R100 is a bolt in alternative to any E4OD with the correct adapter, and these are a better choice if you are swapping in a 4 speed auto in place of a C-6 or manual trans as they have a speed sensor in the tail shaft housing (the E4OD does not). This allows you to use a transmission controller without having to get a speed signal off the rear axle. These transmissions will work with your transfer case.

 The 5R110 is not considered a "conversion friendly" transmission due to the limitations of aftermarket transmission control modules.  It's not recommended to use this transmission outside of it's original application.

See our Cummins to Ford 5R110 Torqshift article for more information about the 5R110.

Ford Manual Transmissions

Ford 5 speed- This transmission was introduced in 1987. It is rated for 420 ft.lb of torque. 95 and newer transmissions are rated for 470 ft/lbs of torque. We make adapter plates for these transmissions as long as they were behind a 7.3 diesel or a 460 big block. We make two styles of adapter plates both of which use the Ford 6.0 diesel starter which doesn’t require grinding of your transmission or starter.  It is important to know that the 7.5L gasoline and 7.3L diesel transmissions have different bellhousing bolt patterns. 

Ford 6 speed-  
Although this transmission did not come as original equipment in these years it can be used in these trucks as we make adapters for the 7.3 and 6.0 diesel six speeds. We do not currently make an adapter to the V10 6 speed. Ford started using this transmission in ’99. If you plan use your truck for heavy trailer pulling, you may want to consider swapping in one of these transmissions as they are rated for 520 ft/lbs of torque. We have transplanted the ZF-6 speed into 80-97 Ford trucks, so using one of these transmissions is possible by modifying the transmission cross member and floor. If you have a fuel tank directly behind the transmission you also have to hammer one end of the tank to make room for the six speed transfer case if your truck is a four wheel drive. Your transfer case shifter can be replaced with a Super Duty version which works better by modifying the Super Duty bracket. You can still use the existing hole in the floor. We recommend using the 03-07 ZF-6 in a swap as no grinding to any part of the engine, transmission, or starter is required. Please be aware that despite the fact that the ZF6 has an extra gear, both the ZF5 and ZF6 share the same final drive ratio, which means you won't see a lower RPM in the overdrive gear.

NP 435/T-18/T-19 4 speed-  
We do not recommend using one of these transmissions behind a Cummins, but it is possible if you insist. The 435 is identified by an aluminum shift tower. The T-18 and 19 both had cast iron shift towers. The T-18’s have a case number of 1301. We can adapt to these with our custom flywheel (FCPN 1406, $ 595.00) and our adapter plate. You will also need to get a bellhousing from a T19 (case number 1309) from behind a 460 or a Ford diesel (6.9/7.3) for the necessary clutch clearance (if you don’t already have one). You will need a 12” clutch disc and pressure plate for a Ford diesel (6.9/7.3) that had a T19. You will also need a ½” starter spacer. Keep in mind without an overdrive your top speed is very limited, and although these transmissions have a reputation for being tough, they are not as tough as the newer ZF transmissions because of their smaller input shaft.

Parts Information


Minor grinding of the oil pan rail on the engine block is also required for starter clearance. More detailed and specific information on our adapter plates can be found on our product pages in the Parts Catalog or by following the links in the kit builder.

All adapter plates for automatic transmissions original to these years use our torque converter adapter ring along with the Dodge flex plate(1994-2006). Manual transmissions use the appropriate Dodge Cummins flywheel and pilot bearing.
Our adapter plates are built out of aircraft quality aluminum and they replace the existing adapter on the Cummins Engine, making a factory quality connection between the engine and the Ford transmission.


Mounts are designed for mounting in two original mount plate holes on your cross member. You will need to move the transmission back about 2 ½ inches, requiring your drive shaft lengths to be changed at a machine shop. This allows you to use the engine driven fan on the Cummins. Some of our customers choose to leave the transmission in the stock location and use electric fans; however, we do not usually recommend this. We’ve heard back from more than a few who have cooling and A/C problems. Electric fans probably don’t save you any money or time in the long run, but they are possible to use if you would prefer. You would need to do some work on the cross member for the different mounting placement, as there is no flat spot on the cross member for the engine mounts to sit when leaving the transmission in the stock location.

WATER NECK ASSEMBLY (thermostat housing)

If you are using a 93 or newer Cummins (having an upper radiator hose connection that points to the driver’s side) with the Ford radiator that has the upper radiator hose connection on the passenger side, we offer a water neck that points straight up. This arrangement makes your upper radiator hose connection quite a bit easier. This assembly also includes the required different sized thermostat and a mount that bolts to the water neck that enables you to use your existing upper Dodge alternator bracket.


Bushing kits include adapters to put your Ford gauge sending units into the Cummins engine along with a compression coupler for your power steering line. There is also a Tee line that works by bringing together your vacuum or hydro-boost system.


When using the 12 or 24 valve Dodge alternator, an external voltage regulator is needed to replace the Dodge’s PCM regulating function. In our experience these work better than an internal regulator that is available for these alternators. The kit also includes a wire pigtail connector and a condenser. 99-02 Cummins swaps may use the optional Dodge PCM to regulate the alternator. 03 and newer engines use the required Cummins ECM so the regulator isn’t needed. Some 80-97 trucks already have an external alternator regulator on the passenger side inner fender. If your truck already has it you can use it again by re-wiring it to the Dodge Cummins alternator.


Our conversion friendly manifolds work much better in the conversion for the 12-valve and 98.5-02 24-valve engines. These manifolds place the turbo in a better place for a/c component clearance than the stock variety, and also make exhaust and turbo oil drain connections easier as well. The conversion friendly manifolds improve air flow over stock and are 2-piece to prevent cracking.

12-Valve Engines

When using a 12-valve engine for your conversion with one of our manifolds it is required that the housing of the turbo be re-oriented so oil feed and drain are vertical. Once the housing is re-oriented, the waste gate actuator will interfere with the engine block. To remedy this issue, we offer a conversion friendly waste gate actuator kit (DCS Part Number 3048) to fit the H1C and HX35 Turbos that came factory on the 12-valve engines.

24-Valve engines

When using a 24-valve engine for your conversion with one of our manifolds we recommend upgrading to a 2003-2004 Common Rail or similar style turbo . Due to the design of the waste gate actuator on the stock 24-valve turbo it makes it difficult for the housing to be re-oriented. Using a 2003-2004 common rail turbo alleviates this issue.


Along with replacement manifold gaskets, hardware, and turbo mounting studs, we also offer a flexible turbo drain tube that connects to the stock hose and elbow that is left in your engine block when the stock drain tube is removed. The flexible drain tube makes for an easy connection to the re-oriented turbo housing.


The tach kit consists of three parts; the Mounting Bracket, Sensor, and Tone ring. These parts are necessary to make your factory tachometer work.

 Providing this signal to your Ford PCM computer also is necessary for the air conditioning, transmission temperature, and other gauges to function properly. All gas and diesel trucks require the tach ring that bolts onto the front of the Cummins crankshaft balancer for the sensor to send the correct signal which makes the tachometer work.

 It is not necessary to buy a diesel instrument cluster for your truck.


We offer two types of transmission controllers for these trucks- See our Automatic Transmission Controller article for more detailed information.

We offer the PCS controller that works very well but a laptop computer is required. We recommend this controller as it has many good features- including two switch-able calibrations and fully adjustable shift and torque converter lock up points.
Both controllers are shipped pre-programmed with wiring instructions specific to the year of your truck, and we are available for technical assistance with installation and use of them.

If you do have a laptop the Compushift controller for the E40D is user friendly and does not require a laptop computer. It is very helpful to have the programmer/display box so it is highly recommended that you purchase one with the controller.


We sell a Brute Force air filter, pipe and hose to connect to your turbocharger. Two versions are available; one style puts the air filter right between your passenger side battery and the radiator. This style requires a bit more challenging to make passenger side intercooler tube than the other kit which puts the air filter right behind the passenger side headlight where the passenger side battery is now (this requires the passenger side battery to be moved over to the driver’s side).


This manifold bolts to the back of a ’94 and newer Dodge a/c pump, making the a/c plumbing less of a challenge. All you will need to do is have some new hoses crimped between our manifold and your Ford pieces at the drier and evaporator. If you would like, you may send your Ford lines and have us crimp the new hoses to the new manifold for a reasonable price.
The 94 and newer pump works fine in these trucks, but you may have to move the power steering lines on the engine cross member and cut a hole in the cross member to allow access to the manifold mounting bolt.


We can also provide you with radiator hoses, along with a custom bent lower hose connector tube. Most of the hoses that are included in the kit are not hoses your local parts house will usually stock, but we have what works in stock at a reasonable price.


Intercooler- any Super Duty ® diesel intercooler can be added to your truck, welding and cutting is required. There are some rare versions of the Super Duty intercooler that have one neck that angles out instead of straight back- stay away from this one, unless you are running a 460 radiator. The 93 Dodge intercooler is also an option and in some cases works better than the Super Duty intercooler. The 93 Dodge intercooler is smaller and can be a bit easier to fit into an already cramped space. Either option you choose will take some work to make the brackets so you can mount the intercooler onto your core support.
Additional battery - not completely required for previously gas powered trucks, but certainly not a bad idea.
Intercooler pipes- usually modified Dodge pipes work or you can sometimes get some bent out of scratch, or piece one together out of mandrel bent sections.
Cruise servo- If your truck was a 94-97 Diesel it used the Ford PCM for cruise control. You will have to install a gas powered truck’s cruise servo according to our wiring instructions. If your truck already has a cable operated cruise control, you will just need to weld the Ford throttle cable bracket onto the Cummins throttle bracket and reuse your original throttle and cruise cables.
Gas pedal- The gas powered truck’s gas pedal will replace your Ford diesel’s “fly by wire” pedal so that you can connect the Dodge Cummins throttle cable.
Automatic transmission equipped trucks will require a throttle position sensor. Depending on the year and what transmission your Cummins engine had on it originally, you may need to purchase a throttle position sensor, or look into other options. All 24 valve engines already have a throttle position sensor that can be used for the transmission controller.
Exhaust downpipe - If you have the cast iron elbow on the back or the turbo a Dodge Cummins downpipe for an engine the same year as you have is a good start to get the exhaust under your cab. Be prepared you will most likely have to make some modifications to it, but it’s nothing an exhaust shop can’t handle or yourself if you have the ability to weld. If you are lacking the cast iron elbow we have a downpipe starter that allow you to use a V-clamp (included) to clamp the starter piece onto the turbo flange. Please be aware this is not nearly as long as a traditional downpipe so you’ll have to add to this to get out of the engine bay.


Give us a call and find out how Diesel Conversions ® can do a professional conversion on your truck for a reasonable price. We have an international airport for travel from and back to our shop, and also can help with shipping options getting a disabled truck here.

This information is provided to you to help you make an informed decision on your conversion. If you have any questions do not hesitate to CONTACT US.

*Diesel Conversions ® is not affiliated with Cummins, Ford, or Dodge. Our use of these and other registered trademarks is for descriptive purposes only.

Diesel Conversions ®
Diesel Conversion Specialists


Knowledgebase Topic:
Make of Truck:
Year of Ford Truck:
Adaptable Transmissions:
Ford 460 C-6 AT
Ford 6.9/7.3 C-6 AT
Ford 460 E4OD AT
Ford 7.3 E4OD AT
Ford 460 ZF5 MT
Ford 6.9/7.3/7.3PS ZF5 MT