So I found a 1990 F250 Two Wheel Drive that has a 7.3 IDI with an Automatic OD Trans and I have been looking for a Running Driving Donor for my 1975 F250 Highboy Project but I'm not very knowledgeable about the Differences and which is the Better Engine. I have driven a friends 1999 7.3 Powerstroke and I was very impressed with the performance it had but again I don't know the Difference between the two. Anyone who has had both could you tell me what the difference is or your opinion on both?

 

The 1990 IDI has MUCH less performance than the 1999 Powerstroke. You can add a turbo kit to the IDI and come close to the Powerstroke performance.

 

Here is a little history on the Ford Diesels.
7.3 IDI is mechanical Injection, and 7.3 Power Stroke is all electronic fuel injection.
Two totally different engines .

https://www.ford-trucks.com/forums/1372495-know-your-idi-history-ford-diesel-101-a.html

Charlie

 

Also, you are going to have a much easier time swapping an IDI(or 12V cummins) into an older rig like that - Both are "one wire" motors.

The 7.3 PSD needs a lot more wiring and electronics to run at all.

 

Both are good engines factory idi has less power bothe get good milage idi cheaper usually. Bought a complete 87 for 100$ and it ran trani needed work but it was a c6 6.9 4x4 truck. Almost picked up another for free an 86 c6 2wd. Wont find a super duty for that price very often. I put a 7.3 in a 73 ihc 1310 was easy very few wires to make run. Have a factory turbo engine in my 94 right now it just wont die. Rolls down the driveway in gear wont start at minus 5 celius or colder now have to use ether.

 

As said, stock to stock, a NA IDI will be around 120rwhp and a 99 psd will be around 190rwhp. With a turbo kit and turning up the pump, and IDI can expect to achieve 200whp or more, vastly more with aftermarket parts. Used turbo kits are out there for the IDI and can be had for 600-800 dollars typically. The IDI will be much much easier to make run in an older pickup. I have an IDI in my 79 F350 and the zf5. Be aware that the NA IDI still produces a vast amount of torque, so it will feel considerably stronger than 120hp. I replaced a 400 in my 79 that had a RV cam, intake, headers, and 650 edelbrock. The 400 was faster, but put any weight on and the IDI was far superior. I also went from 13-15mpg (4spd) to 18-20mpg, this was NA, ZF5, 3.55 gears and 35" tires.

With yours being a highboy, you are going to run into more of a challenge as the hiboy frames are narrower if i remember correctly, its doable, but you have to notch the frame for the starter, and you will have to lift the engine to change the starter. The engine will sit higher in the hiboy, making a body lift a must for a zf5, and likely for the E40D or extensive transmission tunnel work. If you use a married 205, you can bolt it to the ZF with minimal modification, the 1356 doesnt fit in the frame without frame notching, and case grinding. If you plan to stay divorced t-case, you will need a short tail trans, i believe they can be found in vans and F450 Superduties (obs superduty), the superduty is a 4x4 trans with a pinion brake, and probably the easiest to make work. I think all of the autos use a slip yoke, so not sure if that route is even possible.

Physically, both engines (assuming turbo kit for IDI) will take the same work to install, less if you stay NA on the idi and will allow better placement for weight distribution and oil filter to differential clearance (relocation for the filter may be necessary without a lift). Wiring for the idi is reletively simple, as is the fuel system changeover, i used the stock ignition wire to run a relay for the injection pump and glow plug controller power. Fuel system can stay the same, just minor hard line adjustment to connect to the idi lift pump. For the PSD, the 99+ use high pressure frame mounted lift pumps, you will have to plump it in ahead of the tank switch, provide power, and proper lines / return. To run the PSD you will need the computer and associated hardware. I dont have a clue what all that entails.

I built my own engine mount towers, i was able to reuse my transmission crossmember, but it had to be moved back. The holes were already there on top, but had to be drilled on the bottom, i think they were the holes for crossmember for divorced t-cases, but im not sure.