It's real tight in there so I was wondering how easy it would be to install the clip. I sent my headers out to  get NitroPlate coated and don't want to scratch them up having to retighten the bolts all the time. I think I will look into stainless hex head bolts and lock washers.

I use stainless steel socket head cap screws with no lock washers. The reduced head size and size of the allen key makes tight access no issue.
Since day one when I instatalled the "Tri-Y" headers on my 331,  I have yet to find any of them come loose.
Why you ask, well I have to say because of the "Prothane" engine mounts. There is very little movement on these mounts and my guess is that with the lack of twisting between engine and the headers on the engine they don't loosen up.

I don't think the studs would work because the nut diameter would be too big. There is not much space between the header tube and the bolt hole. Most header bolt heads are just slightly larger than the diameter of the thread area.

I had problems back in the day with the Mr. G headers bolts and tri-y headers, as it was such a tight fit and hard to get wrench on there. Regular gaskets would get loose. So, found an old school trick to double gaskets, putting the metal felpro type against head and the cheap paper one or Mr. G ones against header. Never had a problem.  Now, they have the dead soft aluminum and copper ones and the like from earls, Percy's, etc., that don't need retorqed or blow out.  But solve the bolt issue, I found shallow socket (Allen) head.   3/8x1" hardened heat treated bolts in the mcmaster Carr catalog and bought a box. Used them with reused thin Mr.g header washers.....work like a champ for many years.  I will have to see if they have SS ones for when I put the NBA headers on. Hope this helps.