The duration of the Comp Cam is 268/280 advertised or 224/230 with a lobe sep of 110.
You guys bring up excellent points. My intent right now is for a motor to get me going quick again until i can afford a stroked 360 which is $$$$ down the road at which time i would sell the x heads. perhaps i haven't done enough homework -thinking this through and all. Some people say that bolting up x-heads will increase the compression ratio because of being closed chamber as opposed to the open chamber 360 heads that i have on there now. Hence the reason for the .508 cam. Thoughts??????