72 THM 350 mount and bolt thread?

[brown7373]

When reinstalling a crate 350 engine, I noticed my transmission mount had 2 different bolts to attach to the cross member. Since I had the Transmission rebuilt last year, I was surprised that the mount would use 2 different bolts. Or, either they lost a bolt or my truck had 2 different bolts when I brought it to them.

When I reinstalled the (different bolts to the mount, one of them wouldn't tighten up, it just turned and obviously it stripped.

I went to buy a new mount from NAPA, and said I wanted to match up 2 bolts too, and the guy said that might be difficult to match those "odd" threads.

What is the correct bolts for the mount to cross member? I couldn't get any SAE or metric to thread in easily. Maybe a course 3/8 would work, but it didn't thread in by hand. I don't want to strip out a new mount with the wrong bolts.

Anyone else run into this?