I managed to get ahold of a ‘64 fender for measuring.
Like RocknRod mentioned, 6 5/8” from edge to center of holes. For the other measurement I used a fabric tape measure laid flat on the fender from the top butted up to the upper mount. Higher hole is 6 3/16” down and the other is 8 15/16” on center. Hopefully this info is of some use to someone down the road. ✌️
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