The Iskendarian cams can easily be broken into two categories. Neither will imprive idle power on the trail.
The mid-range cam does great for highway driving. Its a boost at the RPMs that most of us drive in every day.
The high end cam is for those who like to scream things a bit more. You won't feel a power difference until higher RPM bands. We don't sell too many of these. Mostly to high-speed mudrunners, hill-climbers, and tough truck competitors.
You do not need to change your rocker arms with the Isky cam. We've sold hundreds and not had a problem with wear. Certainly you would want to check the condition of the rocker faces to make sure they don't bear any scarring or chips. The other catch is to MAKE SURE you put the head gasket on correct. Its easy to get flipped around which causes and oil port to be blocked.... then your head seizes up. Not good. http://www.rocky-road.com/zukengine.html
Feel free to email me at [email protected] if you have other questions. I can check it alot easier than the BBS.