I've been seeing a lot of people talk about getting blower cams and other people getting N/A cams, what's the difference? Other than the obvious, that they're built for cars with blowers.. Do blower cams put out more power with a blower than a N/A cam would? What are the good and bad of each?
Also, as far as the differences in specs for N/A and blower cams....
Superchargers push an unnaturally high amount of air through the intake which allows much more fuel to be burned, and that produces more power. This increases the need for exhaust flow well beyond what stock cams provide (same thing applies with nitrous). Blower oriented cams tend to offer plenty of duration on the exhaust, with less emphasis on intake duration, because air is being forced in. Additional valve lift is also helpful, also for N/A.
The hot N/A cams tend to have a lot of overlap and this is bad for a S/C because exhaust and intake valves are simultaneously open too long. In this case some of the boost gets pushed out the exhaust. On a N/A setup, intake air is not under pressure, so airflow into the cyclinders will be enhanced by the scavenging affect of overlap, i.e, the exhaust is still open and helping to draw in the air coming through the intake.
My experience is with Comp 270's which I think fall somewhat in the category of middle-of-the-road, since they are very good off-the-shelf 'blower' cams and they do well N/A. The increase in output with a S/C is usually double what you'd see N/A.