I did change my chain while doing the valve job because it was about 31/2 degress retarted so even moving the gear the 3 degress it was just a hair retarted so now it is where it isupposed to be, the car has 140000 miles and should run great as the head i bought came with a cam, according to the book it has a couple more degress of duration( more power) can't wait to get it back on the road. if you have the disk it shows how the cam , chain and gears line up