[olddog]

The A9L EEC IV came in Mustang GT 5.0 ltr manual transmission cars from 1989 to 1993 inclusive. I don't always trust my memory. I'm 99.9% sure the 1989 is correct and 100% sure the 1993 is correct.

They are getting harder to find in salvage yards. You can buy re manufactured units at auto parts stores in the USA. I have read on the net that they are not always the correct program in them, but I do not know that to be true. The original units over 21 years old now. Moates.net recommends replacing the capacitors in them, now before one fails and ruins it.

Moates.net sells a Quaterhoarse chip and software that will let you tune until you heart is content. Assuming your engine has the same sized injectors and mass flow meter as the mustang computer expects, it will run ok, but it really should know about the extra 49 cubic inches. It calculates load based on engine displacement and air flow, then chooses the correct timing. It will think the load is higher than it really is and run the timing a bit retarded. It will hurt the MPG and power a little. Or you can take it to a tuner and let them chip it for about the same money.

I know there are people using the newer computers. Some like them better, however I do not know what they do to keep from tripping the engine light without all the newer stuff on the engine. You may want to ask around about that option.