Right noe basically stock cept 2 two chamber flows dumped-those r coming off and bullets going in place of em.hehe Those r good #'s-And yes before and after will be done.

 

M90 (90 cubic inches per revolution) The smallish blower needs to spin fast to make boost, This higher speed combined with a smaller sealing length means leakage at low engine speeds is reduced and low RPM boost increased = full boost by 2000 RPM. So off idle boost, a modified roots strong point, is insane and the increased CFM keeps er breathing up top.
You won't get both from a 3.3L. Off idle is a twin screws weakest point(any off boost condition).
Now that M90 x 2 =

 

M90x2=insane power and neck snapping ability!!!!!!

 

Moregrip, thanks for the more detailed explanation. However, since our factory torque converters on these trucks flash to near 2000 rpm anyway, I guess the low rpm advantage would mainly apply to the stickshift trucks? Also, does anyone know what the difference would be on the topend having to overcome the extra power needed to spin 2 blowers? BTW, how much would 2 m90's and associated bracketry weigh?

 

sounds like a perfect match, flash stall @ 2000, full boost @ 2000.

Any way you slice it, the 3.3 will not be as responsive.

The weight of the brackets would depend on the setup. That's pretty much an unknown as I don't believe any LS motors have gone there.

The M90 is very easy on power consumption though, a little too late for me to chase down specs but I can tomorrow.

 

the advantage is twofold, one; off idle, two; any off boost condition.