Contrary to popular belief, people couldn't just walk up with their glove in their hand and a suitcase in the other and play ball. Bill James in his books often points out that it took the average player of the deadball era the same amount of time to work their way through the minors as it does for an average player today. Pitchers especially were weeded out rather quickly. They really had to have rubber arms. You come across a lot of times in the deadball era where a person pitched at the beginning of their career but they couldn't handle the stress, but were good enough at baseball that they stayed in the league at another position. Someone like Kerry Wood would have gone back to playing third or something, whereas someone with a rubber arm like Zambo would have stayed your ace. As far as speed is concerned, it is hard to say. Obviously they didn't throw harder than pitchers today because that just isn't possible, however, I don't think they threw that much slower on the whole. The human arm hasn't evolved that much in the past 100 years. If High Schoolers today are able to throw mid 80's with no conditioning whatsoever, I'd have to think that full grown men of the deadball era (who were good enough to get signed with and STAY in the majors as a pitcher), could throw at least that hard. It does need to be pointed out that a lot of the older era pitchers were not fastball pitchers per se. They were allowed to scuff the ball, spit on it, and do whatever they pleased to it. So most of them were content to stay away from pure fastballs and work batters on their "shine balls" and "spit balls". I think this also has to do with why people didn't strike out as much in the old days. With the ball moving all over the place, but not all that fast (think knuckleball), players would have make contact but not be able to do much with it. One more thing...they obviously threw hard enough to cause concussions, break ribs, break arms, hands, and even to kill (Ray Chapman-Carl Mays).