Hi, I am a professional certified mechanic, with an engineering background, and 35+ years experience. I will do my best to assist you. Also keep in mind I don't know if you are a pro or a novice so we may have to fine tune the answer. Feel free to add any additional info you feel is needed as we go on. Always keep in mind that I am here to help you with any questions.
I have done hundreds of custom engine swaps through the years and there are a lot of considerations. The full sized Ford diesel engines like the V8 7.3 are too heavy for an F150, also the the fuel consumption is high with these large diesel engines. There are a lot of engines that will fit, but none of them will bolt right in. A custom installation can cost a lot of money. Just the engine alone can cost $3000 to $7000 or even more through normal channels. If you have good sources for engines you might be able to do a lot better. One big consideration is an engine that will match the gearboxes, as far as power levels, and wont develop enough torque to break them. The installation of any Ford V8 diesel would end up breaking gearboxes, and front and rear axles in a situation where the truck was worked real hard, so choosing the right engine is real important to use theXXXXXsystem you currently have.
With all the choices out there I personally would look at the Cummins 4BT. It is a 4 cylinder version of the popular 6 cylinder 6BT used in Dodge 3/4, and 1 ton trucks in the US. I have a 6BT in a Dodge 1 ton truck that has over 600K miles on it, so this type of engine the 4BT, and 6BT are very durable and reliable engines. The 4BT is 3,9 liters and produces the same torque as a 350 Chevy engine. But the fuel consumption is much lower than a Chevy 350. The 4BT will generally produce its maximum torque at 1600 RPM's and this makes it a greatXXXXXengine that doesn’t have to rev real high to do a lot of work. Ford used the Cummins 6BT in some of its larger commercial trucks, and because of this, the engine to gearbox/transmission adapter plate that bolts to the Cummins engines will allow them to bolt up to a Ford transmission. This is super important to allow you to attach the new engine to a Ford transmission. The 4BT, and 6BT don’t have a bell housing flange cast into the block. The bell housing shape, is made up by a plate that attaches to the back of the engine block. This allows these engines to bolt to a wide variety of transmissions, like Ford, Dodge, Chevy, and commercial SAE transmission bolt patterns. The 4BT weighs about 750 pounds and Cummins says it can be used in vehicles that weigh up to 16,000 pounds.
As far as the rest of the installation, the mounts would have to be fabricated, and other custom things like exhaust, wiring, radiator, and throttle linkage. These engines in an F150 sized trucks have produced 25 to 30 MPG in the trucks I have installed them in. A lot of the fuel consumption will depend on gear ratios, and how you drive it. The overall cost will be determined by how much of the work you do yourself, and what you pay for the engine. If you take the truck in and have all this done you could spend $8000+, but if you do it yourself, and can find a good deal on the engine it is possible to do it for $2000 to $3000. Not cheap, but it is a great combination, for bothXXXXXuse and fuel economy, not to mention the extreme reliability of these engines. I will post a link HERE where you can read a bit about the 4BT engines. They were available in several power levels, between 80 and 180 horsepower. Go over all of this, and if you have any more questions, or need any more help, I am here for you. Good luck with it, have a great day, and Thanks for using Just Answer.
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