Try grabbing a couple of these for your 2+2 Ferrari 308 365BB 512BB 400i Alternator Part Number 111680 Algar Ferrari | eBay
On the other hand, we could replace ours with a couple GM units and eBay the takeoffs for a quick $4K.
Or slightly cheaper: Ferrari 308 GTB GTS 308 GT4 Dino 365 400 512 Bosch Alternator 111680 Generator | eBay But you can obtain more cheaper alternatives at your local Fiat Dealer. For instance the EDR 933890. I estimate around 125 US Dollar. See Ferrari 400: Ferrari 400 Alternator / Alternateur / Dynamo
Or, have yours rebuilt for $150 or so Unless it was structurally damaged in an accident or burnt to a crisp in a fire, why would you ever need a complete replacement ?
Origanl Rotor and Distributor cap for a BB 512, will make you think about how you can make them last longer!!