I'm replacing the upper distributor shaft bushing on an early F engine distributor. The new Toyota bushing is 15.88mm OD, but the old bushing is 15.80mm OD. So I'm thinking the easiest way to go is to open up the hole in the distributor housing. It turns out that a 5/8 inch hole is exactly 15.875mm, or essentially 15.88mm. Seeing as how that's not very much metal at all to remove, I was thinking a new 5/8 inch drill bit will open the hole up nicely, and stay centered. But I've also read that a reamer can be used to slightly enlarge a drilled hole. What would be best? Any input would be appreciated.