Timing Gear Drive

I don't know about the 3 hole only question. If it were mine I would try to tap it as long as it was safe to do so. My crank sprocket was tight had to tap on it a little bit is all. One thing I had to do was counter sink the Allen bots behind the cam gear to clear it . I only sunk them by about 1/8th inch. You will need to do the other clearancing that I showed earlier in this thread. I also used red thread locker on everything.