7/8 reverse spotfacer with a 1/4 pilot. brown aviation tools. you'll need to get the pilot to under .250 for a race motor or you'll need to ream the hole to .250+ and cut before you intstall guides. fyi
Yeah I’ve as in the same boat for tooling but with luck I was able to buy out a Retired Flathead builder for his tooling. Best bet is to scout market place or head to a track and ask some of the builders for old tooling.