I was just wondering is y'all had any suggestions or comments on drilling the crank for a dampner bolt? The Power Manual says "Recommended option 1/2 - 20 UNF by 1" deep minimum thread" with a total bolt length of 2.5 inches.

This is for my 250, and this will be an "in the truck" project. Anything would be great. Thanks. John

'68 C-10 - 250 with Edelbrock 600cfm 4 barrel, Offy intake, Hedman headers and true duals, HEI, MSD 6A box, relocated gas tank
Soon to have: T-5 tranny