Raikkonen won't win a race in a B spec Ferrari, sorry Alfa Romeo, because Ferrari won't allow that to happen. More to the point, the car won't be fast enough to give him a chance, so barring a freak weather result, such as Italy 2008, you're not going to see a Ferrari customer car win a Grand Prix.
This is the latest nail in the coffin for Formula 1 being a competitive sport between different teams. The grid is effectively now comprised of four Mercedes (Mercedes and Racing Point/Force India), four Red Bulls (Red Bull and Toro Rosso), and six Ferraris (Ferrari, Haas, and Alfa Romeo). In my opinion, this is both depressing and unacceptable. If Formula 1 is supposed to be about competition between 10-13 different teams, which is what I thought it was meant to be, it is failing abysmally.