i bought some crower cams (264 duration) a while ago and i installed them with the knock pin lined up with the timing marks. the spec. card says i should use a center line of 106 degrees, but i have no clue how this relates to the stock marks. has anyone tried advancing the valve timing with these cams? if so how many degrees out?

 

Interesting question. I would imagine they would grind the cams so that the pulley timing marks would still line up. Otherwise they would have to give you a reference as to where the timing marks should be. I.E., how many teeth to the left or right of the backing plate mark the cam pulley mark should line up with. In the absence of any other specific direction from the manufacturer, I would line up the crank and cam pulley timing marks just as you would a stock cam, as per the FSM, and you'll likely achieve the 106 deg that they specify.

 

Bugs has the right default answer, but whenever I install an aftermarket cam I use a degree wheel set up on the crank (and calibrated against the actual measured #1 TDC) to confirm that the cam makers specifications are being met with the installation. It is all about performance and being a couple of degrees off can make a difference. Offset keys can be used to make adjustments.