Advancing Cam - Need help

This is a continuation of my last post. I have decided to advance my cam timing 4*. The problem I have is when I rebuilt the motor, I remember not being able to get the gear off of the crank. I would get the timing set wih the advance/retard keyways, but I am pretty sure that I will not be able to get that gear off. How can I accurately advance the timing w/out one of these chains. I'm sure I need a dial indicator and maybe some other tools, which I will get, but I just need to know the method to accurately advance my cam timing.

Thanks for all the help!:SNSign: