hey probably a stupid question.....
would early falcon heads fit late model efi?

got an opportunity to buy ported and modified heads to suit 2v windsor

Yes, only the water jackets are slightly different at the manifold face but if you use the Felpro 1250 gasket which have multiple choices for that area they bolt straight on.
The other thing is the early heads use rail type rockers instead of stamped rockers but that shouldn't be a drama if the heads have been set up with screw in studs and roller rockers? You'd hope so if they've gone to the trouble of porting them?
Do you know which particular casting they are?