2.0S vs 2.2S MFI pump
 

What are the differences between the 2.0S and 2.2S MFI pump?

Which one is more suitable for 2.5/2.6 short stroke applications?

TIA

I think they are thesame, but have a different fueling cam dependent on engine dsiplacement. I think either one is fine for your 2.5/2.6 conversion, but will need to have an MFI cam made up for your motor. I think the the MFI vendors mentoned on this site can accomodate.

I'll leave it to the experts to correct me if I'm wrong.

(edit) Pretty good post to start off on: http://forums.pelicanparts.com/showthread.php?s=&threadid=150091&highlight=mfi+ca m

The space cams are different between the two pumps, and they are not interchangeable. I don't know if there is a signifcant difference in the amount of fuel supplied by the two pumps, but it stands to reason that it is likely that the 2.2 pump would be a better choice. Either pump can be tweaked by Gus Phister to be better suited for your 2.5/2.6. I called Gus with the same concern, and he thought that my 2.2E pump would bwe OK in my 2.5 with E cams. He said that the tendency would be for the car to run rich at low RPMs when properly adjusted for high RPM use. I think he said that the internal adjustments he could do would run about $300. I'm going to get the car running and see how it is. Gus did say that the 2.2S pumps seem top work fine on 2.7RS spec motors, so I would think you'd be fine at 2.5 or 2.6.
-Scott