It was D'Arco who, in his book, talked about the max memberships Luciano and the other bosses at the time put on the families in NY. Genovese and Gambinos were 300 each. Colombos were 150. Luccheses and Bonannos were 125-140 each.

I've seen some estimates for the two larger families in the 400-450 range. Valachi may have cited those kind of figures if I remember right. But they may have been inflated. 500 certainly seems so.

Even if we go by the relatively lower figures D'Arco cited, the cap does seem to have changed at some point. The Genovese and Gambinos have each been around 200 members for sometime now. The other families around 100 or a little more for sometime now. One would think they could reach those old max figures, at least the smaller families.

Things may have changed during those years when the books were supposedly closed and few new members were made. A lot of guys died off before they started making a bunch of new ones in the 1970's. Perhaps it was too much to replace so they lowered the cap? I don't know.