Just deadlift as heavy as possible.
On a more serious note, I think you need to look at strength training as a general activity that has the following benefits:
*Increased durability / reduced likelihood of injuries
*A tool for addressing strength deficiencies / imbalances
*A means of reducing motor unit inhibition which can in turn take off nervous system speed 'governors'
*An excellent means of increasing training load and intensity in an easily regulated manner (something which can't always be said for other methods)
*The easiest method (IMO) for controlling peak performance
Looking for direct correlations between weight room gains and speed gains can be maddening. The only place I've seen this is for acceleration (with the squat and the clean).