Hi Mike,
Apples and oranges.
The FEs (427, 428, 406, 390 etc etc) are very different from the 385s (429, 460, 521 etc etc etc)
Different looks, different motor mounts, different dimensions etc etc etc
Two completely different engine series. The only thing that might interchange would be the nuts that hold the carb down
The FEs of course are what some of the original Cobras used...
Tom