Hi,
I have a 57 with a 327, and a full size Exide starter. I was checking the gap between the starter shaft and the flexplate, and find the gap greater than the recommended 1/8". I tried a 1/16" half-shim between the block and starter outer bolt, the gap seems unchanged, then tried two 1/16" half-shims on the outer starter bolt, the gap seems unchanged. I took out the shims, torqued the bolts again, and find a 9/64" drill bit has some slop in the gap, and a 10/64" bit is too big to fit the gap.

I assume I need to get the gap down to 1/8"? The starter bolts are smooth shanked with no knurling. Is the lack of knurling maybe the reason why the shims don't close the gap?
Thanks, Doug