Hi I have an 86 Cougar and I just bought a Marquis that has a 5.0 EFI with an AOD tranny. Is this swap going to be a hard one and will I need to get a new brain when installing it into my Cougar? Also will the mounts match up? I haven't attempted to begin yet and need to be prepared with the first basic questions answered.
The 5.0 will fit, but the grand marquis has the intake flipped the opisite direction. Just food for thought. other then that it should be pretty much the same as your car would normally have. It would be much easier to put a H.O 5.0 in your car while you have it all out, but each to his own.
The intake will flip around but thats gonna be the easy part... I doubt the 3.8 throttle cable will mate to the 5.0 Throttlebody and its doubtful the GM cable will fit the Coug. MAYBE if the left position TB is retained. 99% the motor mounts will not fit the Fox chassis. Exaust will be another issue as the big car stuff isn't gonna fit without some major rigging.
The full size cars also have a much different layout on the sensors, and computer location so the computer harness isn't going to work very well... if at all.
what year marquis? I have a 91 crown vic I can take pictures of. It would prolly be easier to switch the intake and what not around. Maybe get you out of swapping around parts, like the battery tray. Also, the coil is on the brakets for the front of the engine if I do remember correctly, so that would do away with the coil brackets and what not.