what is the depth of the hole in a small block 4 speed crank???????

I have heard that some cranks for automatic cars were partially drilled but not finished out for a 4 speed. As far as the input shaft I would like to stay with the bushings. I don't want to cut the end off of the input shaft. If I can get these measurements I will take the crank to a machine shop and have it drilled. Then everthing will be sent out to be balanced.