Yeah...I understood all of that. I have spun mine above 17k. 5900 may be the most I want to spin my motor. I have had the 2.75" pulley on there and doing 6200 with the stock crank pulley. 2.75" is the smallest radix pulley that I have heard of, so if I want the blower to spin the same speed, then I would need a bigger crank pulley. That is what I meant.

I would however, like to know how the HD trucks can get 14lbs of boost with bascially the same eaton blower and only 5400rpms? Is the design that much different? Can 12lbs of boost be attained without grenading this thing?

 

To spin the blower slower you would need a smaller crank pulley.The way Lightnings and HDs spin that much boost is restriction in the heads plus they only rev to 5400 rpms so a larger crank pulley is feasable for them to use.

 

Show us some pics of your heads and short block