Rally Center Cap Bolt Size?

[Donbarnes]

What size are the bolts that hold on the mid-70's Rally center caps? I can find lots of threads over the years where people have asked the same thing, but no one ever tells the size, they just post links on where to get them. Then the people selling the bolts never tell what size they are? Thanks...

[firedemon]

mine were regular 5/16 coarse thread by 3/4 or 1 inch but the head has groves built in to keep it from backing out don't know the proper name