EFI Problem

Hello:

I just bought a '70 Bronco with a 351W, to which an EFI system has been added. It includes the lower intake from a Ford Lightning (w/fuel rails), upper intake from an Explorer and the computer and harness from Ford Racing. The problem is that when RPM increases, the timing retards. TFI and stator have been checked and everything else seems to check out through the computer (EEC 4 check connection). I've had it to many mechanics; the most recent one suggested that the likely early model motor is not designed to work with a relatively later model intake/EFI and. Another is that it's the MAF.

Any thoughts? Does anyone have this setup, which I understand is not that uncommon?

Thanks.

First there is a jumper to disable computer control of timing when you set base timing is that jumper in place?
next, doesn't the 351 distributor spin opposite of the 4.0?

I may be out of line when I say this but, Why did you buy a Rig that has been tweeked that much without knowing full well what you were getting yourself into.
Please tell me you are in contact with the former owner.
Sorry to be so negitive but, You sound like you bought a rig that has been modified way beyond what many people would be able to handle accept the person that built it.
That said, Why was he selling it.
Like I said sorry to be so negitive but I know I wouldnt fuss with an engine built to that standard. And if I built one, I wouldnt sell it unless I had problems I couldnt fix. If you are having too many problems. Swap, Then "YOU" know what you have and know what you can fix, A good starter motor cost about $900 that you can drop in and go. Note: You can only bring it to the shop so many times before you start hating what you are trying to accomplish. The money spent well be worth the lack of the headache.