deff agree with Dave on that one. Great thing about the mustang computer is its easily re-flashed for upgrades. The last thing you want is to get stuck with a shitty fuel and ignition map because your having a hard time finding someone to re-flash your ECU. I just rode in a truck today, its a 98 but these rules still apply, that had a 5.0 from a 2000 Mountaineer in it, the truck has balls and everything but it should have been much faster. The truck was loading up with fuel for probably a few reasons, A. it had no cats, B. It had cold air intake that im just about 100% sure belonged on a mustang motor. In my opinion ECU was not happy with the mass air meter plugged into it. These problems could be easily solved if the ECU could be re-flashed and or the truck had the correct mass air meter on it and cats under it... to make things even worse the motor had a cam in it. In other words the guy has a motor that sucks fuel and runs at about 70% of what it could. Where im going with this is, the pre-96 5.0 engines do not have OBD2 emissions equipment, they dont have to pass the same emissions standards and since your swapping it into a pre 96 truck, you are not restricted by OBD2 so why put an engine and ECU in your truck that has more computer diagnostics built in. OBD2 SUCKS and it makes the ECU a whole lot harder to tune and remap, thats the moral of this story. My suggestion, Sell that engine to one of us guys with a 96 and newer truck and buy yourself an 86-95 5.0 HO.