Edit the jump rating. It's the only way. I find the block rating next to useless while playing the game, because your player usually blocks the shot if he has hops and is tall (or if you have good timing). Try cutting your player's jump rating a bit.
If you look at my Domination franchise, my 6'6 point guard Corey Harrington has legit hops (REALLY legit hops) and he does FT-line dunks and stuff, but I lower his block rating to 54, but he's such a high-flier, he has no problem blocking seven footers.