[cjperformance]

Its more like 1 lb per 1/10" instead of 1/100th

Its just a rough estimate because it depends on crank pulley size, supercharger size (P1X vs D1X), rpm, and other mods.

But as far as i know going from a 3.85 to a 3.70 on the supercharger side would be anywhere in the neighborhood of .75 psi to 2.5 psi increase at most.

For example, i was making around 9.5 psi with a 4.13 pulley at 6500 rpm, going to a 3.70 its around 13 psi. Thats about .4 inch smaller and about 3.5 or so psi increase, which follows really close with the .9 psi per 1/10th estimate. If you have a smaller or larger crank pulley, the proportions will be slightly smaller or larger.