Is this industrial (?) 391 FE engine worth saving ?
Yes I'd say its worth saving! The block may or may not be able to be used as a 428 block, I beleive it depends on the size of the hole cut for the distributer shaft. Even in that case, re-using the FT dizzy will take care of that. The front cover is wrong for a car application. The Crank can be used in a car application if the snout is turned down to car specs. If it is a true FT, it will be a forged steel crank, worthy of some of the more powerful 427's (390, 406 and 427 share the same stroke) The heads and intake are worthless to anyone except someone needing replacements.
There are a few other things Im sure, but I cant seem to put my finger on the rest.
How much is he asking for it?
Those that say it cant be done should say so quietly, so as not to disturb those who are doing it.