Hi, need to install longer front wheel studs on my 72 dart bracket car. Am running centerline 15x3.5 on 10 in.drums. Where I'm confused is the so-called "knurl" specs. Year 1 says should be .555,but can't find anyplace that sells them.any help greatly appreciated.

The .555 knurl may be the stock spec before swedging the studs in. The larger spec you see may be the size to use once you pull the old ones out, enlarging the hole due to not cutting the swedge interference. The stockers will not fit if you pull the swegies out forcefully without cutting the swedge down (or grinding the heads off and pulling them out the front, no damage there)