Ok, alot of info here... My question is this. How do you decide what amount to flow a combination at? Is there an industry standard that says I have to flow it at say 28# manifold pressure ? just trying to get some more info, before I ask more questions. So what happens when you add boost to the flow instead of vacume? (is this not done on a bench somwhere??)I'm curious because my heads flowed 335 @ 28# , but my Supercharger is pumping 22 lbs boost WOT, with a mild 620 lift solid roller in a 496.(based on a 440) What does that take my flow number too?... How much does humidity affect volumetric efficiency on a flow bench? what about Altitude?... 28# here in Colorado Springs, Colorado is NOT the same as 28# in Miami, FLA.(desinty altitude affects my race car just like in my Cessna 180. most of Us know what it does in the "real world" but is it even factored into the equation? What about temperatures of the air being flowed? AKA...Density. I know that most lift/flow improvements are made to produce gains in a naturally aspirated engines. Most of this technology does not apply to supercharged engines.(beyond the basics) It was mentioned in one of the posts on this topic, the effects of overlap ( the period when the intake valve has already opened, and the exhaust valve is not yet closed.) in a blown motor this is power lost and heat gained to some degree, yet a naturally aspirated motor tolerates this. as Air needs time to get "moving". I'm not trying to change the subject here. just trying to get some better understanding before I build my next motor. I have the use of a Superflow brand bench test stand whenever I want it... Just waiting to build a Larger Air/fuel Pumper!!!! Thankyou.... Grant Eaton 719-330-0468 best time in street legal trim to date 8.03@172 mph at our MILE HIGH ALTITUDE. yup, :Licence plates, ET street tires and no traction!!!!