RE: 91 740 ECU Location????
Do you have a Square coil?
If not then that is the ECM. If you do then I think it is under the Drivers side.
To tell if you have EGR see if you have a Metal pipe that comes off the Exhaust Manifold and goes over to the intake area.
1987 Ford mustang LX Coupe 5.0
1995 Yellow T5-RM running
1996 850 turbo
1994 N/A 5-speed wagon Purple (daughters)