relation/transfer of training tests and 40 yard dash

Just a few thoughts:
1:SLJ and VJ MAY have a slight relationship to 40y- but only if they are an indicator of freshness and recovery- a good indication there would be recent improvement in these areas rather than results alone.
2: SLJ and VJ do not rely on decreased contact time so there can be no direct relationship to 40y.
The World Record in the SLJ is held by a Shotputter and you can expect linemmen to do better overall here than the backs.
Squatting to weight ability should have a relationship- IF the athlete can handle the owrkload associated with his improvement.
Your example is illustrative. The guy improved from 300 to 500 but his 40y remained static. What if he had followed a more modest strength increase regime? He might well now be at 450 in the squat and have a faster 40y.
OR, as I point out in the Weights for Speed downloads, what if the weights followed a pattern adjusted for and catering to his speed work?
Now he might not only be faster, he might squat MORE than 500 because weight strength will follow the speed improvement if that speed work can raisse its quality high enough.
I have seen this phenominon in the 225 bench test as well but you can pass on your thoughts on that when you’re ready.