My B&M blower is running the 10 rib belts and pulleys producing aprox 5 lbs of boost around 4000rpms up to 4900rpm. Does anyone have information on changing the pulleys for more or less boost and at what rpm range? I am new to supercharging and would like to have it for reference.

Thanks

On my 525SCs, I went to the next smaller upper pulley. It gave about 7 lbs of boost.
But the supercharger was spinning REALLY fast. would reccomend leaving it at 5 lbs.

If your talking about the small B&M...its a 174.
I wouldn't push it any more than that...they are weak at best.
Now if its the weiand 177...you could drop a pulley size but it wont do anymore but 1 mph and eat more gas.

Just curious. I will leave it alone.

Good choice....

I've got an older B&M 174, too. Can't get more than 5 lbs out of it no matter what, but it sounds best to leave it that way. It seems like it spins a lot the way it is...

Maybe just find a good 250 blower, generate less heat and burn more gas!