i have a 93 7.5l and was wondering what was the easiest way to make more power out of it it already has a straight pipe and k/n filter but i want to see at least 400 horse is that doable on my engine or not without getting a cam or supercharger

 

you'll likely have to do away with the speed density system to see that horsepower. MAF, or back to carb.
you'll definitly be looking at a cam swap.

 

well as far as going to carb and that is an option what about fuel delivery do i need to change anything or can i use my stock delivery system

 

i was thinking banks headers and i will be running a four in. stack here in a while. but still what about fuel

 

All you need to add to the trucks fuel system to run a carb is a fuel pressure regulator set to about 5.5 psi. Be sure to use a regulator the returns fuel to the tank so the pump stays cool. Then of course the adapter plate for the EFI manifold and the carb.