Crank bolt to hold damper

I myself would spend a little extra and also get a 7/8 ream to go 1/4 inch deep with before tapping and use a 1/4 longer bolt than the factory bolt. Drill overall length 3/8 deeper to bottom tap into. Having the first 1/4 inch or so of full threads on the tap guided inside of the crank itself will help tremendously on getting the tap started straight.