During the Lob City years, it felt like Blake Griffin got his head to the rim every week. I would put his best vertical at about 40 inches. That is a little higher than the 38 inches it takes just to reach rim level at the height used in the video.
Start with Blake's height
The NBA lists Griffin at six-foot-nine. Allow about an inch for shoes, and the working height is roughly six-foot-ten on the court. The rim is ten feet, or 120 inches. Subtract 82 inches of height and you get 38 inches for the top of his head to meet the rim. That is the starting point, not my estimate of his best jump.
Watch the highest lobs from his Clippers years. His head gets to rim level often enough that 38 does not feel like the ceiling. On the best-looking attempts, it appears another couple of inches higher. That is why I land near 40. It is an estimate from what we can see, not a number Blake recorded on a jump tester.
Why the lob matters
On an alley-oop, Blake can use a full approach and jump before the ball gets to him. Compare that with a play where he has to carry the ball, avoid a defender and still finish. The two dunks may be equally impressive, but the clean lob gives me a better shot at seeing his highest jump.
The camera can still fool you. A low angle can make his head look higher against the rim, and the stanchion or a defender can hide the peak. I would rather work from several useful jumps than claim one broadcast frame tells us the exact inch.
Where I land
About 40 inches is my best call for Griffin's highest visible vertical. His power and body control made some dunks look even bigger, but those are different things from jump height. I compared him with Shawn Kemp because their dunks get talked about in similar ways; Blake looks a little higher relative to his own height. The source video also covers Kobe Bryant and Michael Jordan, and the NBA table has all three estimates together.