Okay, I've looked at boltdepot.com, graingers, and fastenal, and even Ford Racing and AFR themselves, and I cannot find a source for brass, stainless steel, or chrome (or any metal, really) threaded plugs for the 5/8"-11 threaded heat pump holes on the front and back of my AFR-185 heads.
Am I missing something here? I suppose I could use bolts, but the elegant solution is chrome or stainless steel countersunk hex (Allen) plugs.
As I'm not in a total hurry as I assemble my 331, I've got time. However, there is a point at which one must admit this effort is ridiculous---hmm, I've already passed that point, now, haven't I?.
Anyhow, sage advice welcome.
Where (Oh, where!) can I obtain these plugs?
DD