if i remember right, they only drill one hole in the gear. you install the new gear, line up the existing holes, & run the drill in thru the lined up side & out thru the other side using the other existing hole in the dist as the guide. guarantees alignment of all holes.

 

If your lucky it will line up with the original hole at the correct installed height....if not, drill the new hole 90 degrees to the original hole. They are a tight fit (usually) and you have to press the gears on and off. Above all, pay particular attention to the installed height of the gear....its very important to get it right.

 

Be sure to measure the distance between the bottom of the original gear (installed) and the end of the dist. shaft. This is critical for resetting the gear on the shaft.

The hole is basically randomly drilled and sometimes at an angle that doesn't match your current hole so be prepared to re-drill the shaft/gear.

Press off the old and press on the new (setting the gear at the appropriate clocking relative to existing holes). Watch your installed depth. Drill. Pin.

 

I just sent my Dizzy with new gear to MSD. For $38 bucks they did it all. No Problems.
Mike