I'm thinking these numbers are what you can creep up on but not go over. In other words, what they will allow. The good and bad thing about the 69-383 height, good for compression,bad because the valve hits when using the spec 440 cam.
Someone building an engine to compete in the class is going to build to the max allowed if they want to be competitive otherwise why bother.
The 68-69 383HP road runner/superbee engine and the 375HP 440 Magnum used the exact same cam.
