I've never seen a stud on those. Every 460 I've worked on uses a bolt to hold the clamp, but maybe they did when used in trucks, etc. Maybe someone thought differently at one point and installed one? At any rate, I'd simply remove the stud and use a 3/8" bolt for your hold down.
As far as your heads? They're pretty much the hot rod standard of 429-460 heads without going crazy on D2OE's, CJ, SCJ or Aluminum. Supposedly 75-77cc chambers, Paul Kane could tell you more, but my understanding is they measure more like 68-70cc, which allows for more respectable compression using normal dished 460 pistons. Different versions of the D0VE head, the A's through C's are kindof hit and miss as to which have the thermactor humps and EGR passages, but the same end result can be had with any of them.
You got good heads, in other words.
Ray
