[Chief]

Cheap mods, K, would be a K&N air filter....and yep, a low-restriction exhaust. Also...Banks Engineering is the country's foremost diesel performance specialist. www.bankspower.com
I know that pumps can be "turned up"...whether or not you can turn that one up, I don't have a clue...

[HotRodTodd]

I do conversions and mods for Banks Power and if you have alot of money that is the ticket. 84 is not a good year to be modding im afraid. You didnt mention a turbo, im pretty sure that in 84 it didnt come with one. If thats the case thats your biggest improvement to start. If you can find a turbo and the plumbing etc at the bone yard then you have got a chance of getting that slug of a motor to breath. Then you get into the injector pump and change the fuel curve, then you chage the injectors to high flows. If you have to buy the complete kit from banks with turbo, it is around 4500.00. So you may want to find a newer truck to mod, it may be cheaper.

[HotRodTodd]

Well there is an old saying, speed costs money, just how fast do you want to go? Like i said before, if you can find a newer ford at the bone yard and get the turbo and plumbing off of it, thats going to get you the most bang for the buck. Hell there should be plenty of dead fords you can get parts from. They are quite plentiful. If you are familliar with diesels they were never designed to run without forced induction. They are not efficeint without a blower or turbo to help them breathe. That propane kit will help slightly but its not cheap either. The company that makes them is called Bullydog Performance. They do not recomend installing the kit on non turbo diesels though. Good luck.