The Greatest Baseball Pitchers in History

What's a statistical way to rank how good pitchers were? I think the fairest way to do that is to determine how much difference existed between a pitcher, and the team(s)he pitched for. For example:

Walter Johnson - taking out Johnson's first and last years in the majors, when he pitched only around 100 innings each year, his lifetime record is 407-264. A winning percentage of .607. Over those years the team(s) he played for, the Senators, went 1425-1438. A winning percentage of .498. So Johnson's winning percentage was .109 better than the team(s) he pitched for.

That puts Walter Johnson in 5th place all-time. Any guesses who's above him? You might get two, but unless your really a stats nut, you'll never guess the other two. In all, there are just 8 pitchers at or above .100.

A few notes:

I didn't rank any active pitchers because I haven't had the time to run the numbers. When, and if I do, I'll post the active leaders.

If a pitcher did not pitch over 100 innings in any given year, I left that year off the rankings. If a pitcher throws 70 innings and goes 2-5 for a team that wins 60% of its games, it's not an accurate reflection of that pitcher. The pitcher has to have a real and large impact on a team's record to count. Here's the eight, and some notables.

1) Grover Cleveland Alexander - .121

1) Sandy Koufax - .121

3) Sal Maglie - .112

4) Jesse Tannehill - .110 (if you got him and Maglie, I'm impressed)

5) Walter Johnson - .109

6) Lefty Grove - .102

7) Cy Young - .102

8) Tom Seaver - .100

Other Notables

Ford (.092), Guidry (.089), Mathewson (.085), Gibson (.077), Marichel (.075), Carlton (.066), Spahn (.061), Feller (.052), Sutton (.026), Ryan (.024), Drysdale (.011)