I am installing a 2000 Lightning blower and intake manifold on a 98 5.4L, I have nearly all the loose ends tied up, I just need to know at what engine or blower rpm you generate 6psi of boost. Also, does anyone know the diameter of the crank pulley that drives the blower?

 

7.40". i've never been at 6psi

 

We can get 6lbs???? I though it was vac then 8lbs, then I got a lower pulley and it was vac then somewhere past 10 on the guage???

J17 - since these are roots blowers you will get full boost well below 3000rpms, it's almost like by the time you floor it your at full boost.