When i did mine i just did a little at a time with a drill bit until they fit. Take your time and you should be fine. You don’t want to rush. I used a 92 TPI base and put it on the old style heads.
When i did mine i just did a little at a time with a drill bit until they fit. Take your time and you should be fine. You don’t want to rush. I used a 92 TPI base and put it on the old style heads.