<font color=blue>Duration is the period of time measured in degrees of crank rotation, that the valve is open. Duration is the deciding factor to what the engine’s basic RPM range will be. Lower duration cams produce the power in the lower RPM range. Larger duration cams operate at higher RPM, but you will lose bottom end power to gain top end power as the duration is increased. (For each ten degree change in the duration at .050”, the power band moves up or down in RPM range by approximately 500 RPM’s.)</font color=blue>
It would have been cooler if I claimed that to be my own piece (hehe) but that is from a Cam mfger`s website and pretty much sums it up Scott. Low gears,4 barrel,more of a street orientated performance , then go with a 270 or 280 but a 304 , stick with the 260 . There is a company here in town that custom grinds cams and he said the BIGGEST mistake is people ordering to large of a cam for thier motor. You mention the idle ? Hey I used to have a COP 427 69 Chevelle and I want everything to idle like that thing did (hehe) but it aint going to happen my friend [img]/wwwthreads_images/icons/smile.gif[/img] .
<font color=black>Summer is just around the corner [img]/wwwthreads_images/icons/tongue.gif[/img] </font color=black>