I just picked up a 91 f250 7.3 today. It has 165k miles, but is in great shape. My question is, do they make any chips for that engine that boost performance without doing any damage to the engine? If so how much do they cost? I will post pics as soon as I get them.
Thanks in advance,
Lars

 

Is there a computer on your truck?

 

The 1991's doesn't have computer controls for the engine. If you want more power and better mileage. Then open up the exhaust (larger diameter or lose the muffler), open up the air intake (cut soup bowl out, install K&N) and have your timing checked.

There are other tricks but you need to get a pyro before doing other power mods. After getting a pyro (exhaust gas temp) you can turn up the fuel setting on the inside of the injection pump. THis can be done without removing the injection pump. There is an access cover on the passengers side of the IJ pump. Then rotate the engine (by hand- with all electrical disconnected from IJ pump). When you get the engine rotated to the correct place you will see a set screw deep inside the access hole. If you turn the screw clock-wise it will turn up the fuel rate, counter-clockwise will decrease the fuel rate. Only make small adjustments to this screw, 2 flats is about the max without a turbo. Then you need to keep an eye on the pyro, you can achieve thermo-nuclear-meltdown, so keep the temps below 1125 degrees, and nothing sustained above 1050 degrees. Or you will melt the valves and pistons, which lead to a dent in your bank account.