General 5.0L Fox Swap and EEC Info
1. The first Fox was the 78 Fairmont. In 79 the Mustang and in 80 the TBird got it. From there to 93 many more cars were added like the Cougar, Mark7, Capri, little LTD and even the Granada for a couple of years.
2. The two areas where the most changes must be made for this swap is in the fuel line routing and engine electronic wiring.
3. The Turbo Coupe used in the video comes with an 8.8” rear end. Most other Fox cars will have a 7.5” rear. An 8.8” rear from a Fox 5.0L Mustang should be on your “to get list”. The 7.5” is really not strong enough for any performance build.
4. All Fox and SN95 rear end housings have the same control arm mounting points. Axles shafts are longer on the SN95 and control arm length are different on some models.
5. The 86-88 TBird and other models that use the hydro (liquid filled) motor mounts may cause a clearance problem with some shorty headers.
6. When roller rockers are used, some 5.0L valve covers will not clear them. Removing under cover baffles or adding gasket spacers are two fixes. Taller valve covers work except they may hit the upper intake.
7. It appears that no TBird 5.0L EEC harness is a direct fit/swap for a turbo or even a 6 cyl. body wiring because of component differences. Some Mustang harnesses can be swapped of the same year model if most of the body harness is also used. However from a practical standpoint, it may be easier to just add a donor EEC harness and make the needed interface connections to the existing body wiring like in the video.
8. I had to replace my fuel pump because it was damaged. I do believe that a fuel pump upgrade should always be considered when doing a performance swap. Might as well install a 255 lph unit while your at it.
9. Adding a MAF wire harness is easy as shown in the video. Be aware that some MAF PCM’s will have different pin connections for some sol./sensors (smog pump solenoids come to mind) so be sure to check a wiring chart for your new PCM.
10. Over the years the 5.0L had 6 or more different timing chain covers, however there are two main styles. One type for standard rotation (clockwise rotations like the crankshaft) water pumps and the other for reverse pumps (counter clockwise). Be sure your project has the correct chain cover for the water pump your using.
11. 5.0L engines with roller camshafts must use distributors with a steel gear. Earlier non-roller cam engines had distributors with cast iron gears. Never use iron gears on a roller cam.
12. All EEC 4 systems use an inertia safety switch. It can be wired between key power and the pump relay’s coil however it’s best to wire it between the relay’s output and fuel pump. This method wires and troubleshoots easier for an engine swap or EFI street rod.
13. Understand, every non-stock 5.0L engine/head/cam combo is slightly different so valve lash, rocker geometry and piston to valve clearance must always be checked.