EFI computer

[Kenny]

Hi, first post here but long time 57 custom 300 owner.  Car was bought new by my Grandfather and has passed to my Dad then to me and will eventually go to my son.  I am starting a swap from the original 272  3 spd manual to a nicely built 302 EFI from a Mustang GT.  Will have an AOD with transbrake etc behind the 302.  I have already installed rack and pinion steering and will be putting in Vintage cool.  I also have the Mustang donor vehicle.  I have read every post on swaps and examined the wiring diagrams for the Mustang and was wondering if those of you who have done this change can indicate what feeds to and from the computer you did not use?  There are systems on the Mustang that just are not on the 57 of course and I am somewhat concerned it will not run if some of those are not hooked up.  Things such as the Air pump systems, maybe the EGR, purge valves etc.  Any advice would be greatly appreciated.  Thanks!

[Ford Blue blood]

Easiest thing to do is contact any number of the 5.0 suppliers.  There are so many plug and play harnesses available for that engine/transmission combo it will make your brain hurt.

If you are handy with prints contact Helm Inc. and order an electrical manual for the donor vehicle.  I put a Continental 302/5speed into a 66 Falcon Ranchero.  I disconnected the "Thermalctor system", "EGR", and "Tank purge solenoid" from the computer and had no problems with drivability.  Looking at the prints and doing a little research on EFI it is easy to figure which are inputs to the computer and which are outputs.  (FYI, most of the outputs provide a ground to the device.)

Both the Speed Density and Mass Air systems will break down to a four wire hook up with the current electrical system.  They are Ground, +12V keep alive, +12V start and +12v run and last but not least a control line to turn on the fuel pump(relay control).

[RICH MUISE]

Welcome to the forum, Kenny. From Bill's response, you can probably tell why he is our go to guy on electronics. I'm a big fan of Ron Francis Wiring's quality, so I'm glad it's them that are about the only ones that make a harness for the 4.6 I'm installing..they also have a bunch of 5.0 harnesses available, and I know Painless does also.
Rich

[Kenny]

Thanks for the quick response guys, you have pointed me in the right direction and I now have to decide which harness to choose.  I have read the Ford Racing Harness installation directions and it sure seems like exactly what I want.  I will research the other ones as well.  Can't wait to get started!

[canadian_ranchero]

when you disconnect the egr,you can run into part thoddle spark knock