This is a new ad today on Ebay, for a Immerson MFI system. In the ad, it's said that they may have been designed and made in the 60's and only 10 were made. There a lot of picture to look at. I don't remember them them, how about you, Cammer?
I'm posting this here, not as a ad but, as a historic FE part so, more members might see it and a conversation might develop. I have nothing to do with the selling of this.
Here Immerson has adapted a early Chrysler Hemi, Hilborn manifold to the FE. As I remember, that engine has 4 9/16" bore centers and matches up well with Ford's spacing, only about 1/16" off.
Has anyone ever heard of Ernie Immerson? He must have been heavily in the FE, to do this!
Enjoy:
https://www.ebay.com/itm/175294247546?hash=item28d059f27a:g:xhUAAOSwGKxijTIO