Manifold bolt?

should be 2 studs / nuts

Wow…wax…who knew!👍 I will see what I can do.

Another pic….

Anderslober wrote: And another…(I still dont know how to upload more than one photo in a post)

  

Tip, just barely brake loose all related bolts before fully loosening any of them. The extra pressure from having some bolts out adds slightly to the others.

A six point with the little grooves at the angles will be the best bet adding to what Rock posted. Especially if they are slightly rounded off.

radiused corners don't really help the bolt come loose, Snap-Off patent was to reduce stress risers and broken sockets/warranty costs. They have dazzled everyone with bullsh*t about "Flank drive" for years.

There are repair items made to replace a broken and seized stud etc. Find those and see if they will fit onto that one side. The one I'm thinking of is like a pair of steel bars that attach by long bolts of their own, sandwiching the ear of the collector and lower flange. Kind of like a clamp, it squeezes the old flanges(the small section where the bolt is) together with the down pipe flange. They are on Amazon and I think they were about a $25 item. I believe it requires a decent flat surface on both parts to clamp onto, but you can grind and file down that worn hole area to do that.

 its drilled out...i's rethread it, or if needed drill it larger and helicoil it to the correct size, or since there's room use a bolt that is long enough to go down towards the pipe (grind part of the bolt head to fit against the manifold)

Manifold looks good. Except the drill out hole…

Wow…ok….that means this is original and untouched basically.

Run a tap and use a heli-coil (there is a better coil replacement system but I forget the name). That setup will work but you already have  the manifold out so why not do the other one as well?