I run mud and sand drag, blown alc 572 and my current combo is making 22psi and my problem is the car lays flat, change timing, fuel, clutch adjustments but the power hits a wall at 22 psi. The theory I'm working on right now is that my Promag 12 just isnt enough. If I change pulley config to achieve 19 psi, it starts to pull but just not as hard as it should, at 22 the car launches hard and just pretty much stops pulling at 7000 rpm. Just hoping to get input from anyone with experience with this, I don't have anyone close I can borrow a bigger mag from to rule this out and its a bit expensive to be wrong about it. I just had a disappointing weekend when it hit me that I ran into this once before with a msd 6 on a blown alc motor, did 11 psi and that was the barrier. This is my first post so I should apologize for not being familiar with posting.