There are a bounty of insufficiencies in the novel and movie that are grist for our posting mill. The size of the Corleone family is one of them. We read and see the family with, principally, only two capos. Sonny has a regime, but after his death his regime personnel are distributed among Tessio's and Clemenza's regimes. So, we're back to two. That seems improbable. If, as Sonny states, the Corleone family can match the other families gun for gun, then he's talking about 1,000 men (I don't buy one Board members's argument that those 1,000 guns would include associates recruited just for that purpose). If the Corleone strength is that great, then only two capos would be an administrative nightmare for Tessio and Clemenza.