[Barry_R]

As another supplier of FE 2x4 carbs I could tell you that the 1850's wont work. BUt that would not be true. They will work pretty well once you sort out a couple things.

The linkage needs to be tweaked. The factory Ford linkage was progressive and does not readily mount ot the 1850's universal style side plates. You need to either add a hole or to fabricate a spacer for one of the links.

The throttle plate on the 1850 has a PCV valve fitting that extends out from the center. This fitting needs to be removed, plugged and milled flush. The passage below gets uncovered on some intakes causing a vacuum leak. I still catch this sometimes on my carbs if the guys "forget" and use a normal base plate.

You need to make certain that the throttle plates are well centered in their respective bores and very nearly closed all the way - you should only see a very small amount of the transfer slot from underneath - perhaps .020". Too far open and you'll have a high idle speed and unresponsive mixture screws.

Once sorted out the 1850s will be just fine.