I would like to know why non fuel injection heads are not able to be used on FI motor when continuing to us FI?

 

not for sure on this but they have different size ports and the valve angles are different not to mention the bolt pattern is also different Like I said not for sure so if there s any one who is speak up!

 

alans77crew that is basicallly it, due to the difference in the intake bolt patterns the intakes physically won't bolt up. but the valve angles are not revised just the intakes are different ports and bolt patterns.

 

I just tried matching up the gasket for my 86 engine to the 93 EFI heads. The bolt pattern appears to be the same, but the intake ports are higher up in the casting. This was just a quick check (the heads are still bagged up). It looks like you could switch intakes, but you would have one H*** of a leak. I do know that Ford changed the PNs on the valve train components too.