Of the FE's the 390 is probably the most sensible option out there, shorter stroke and reasonable cyl wall thickness make it less fragile and unlikely to suffer from porosity problems that are common on the larger 4.130"/4.250" bore variants. Resist the temptation to stroke n poke it and be sensible with cam head carb choices & it will last a long time. I built one for a Hot Rodded 56 Ford Sedan back in the early 80's & this guy approached me recently ( who I thought I should know, but could not put a name too
) and informed me that it is still going strong & has not had the heads or pan off yet! When He first got it he did not exactly treat it with kid gloves although I suspect he might have mellowed a bit by now.
Jac Mac