Here is what it looks like 67 b-Body 426 with hemi pan. Measurement from bottom of block to the drag link 2 5/8" you can't get a pencil between the pan and drag link. If the idler arm is good the the drag link does not move up and down just side to side.

A 187 pan is 2 7/16" in this area.

So I don't know what was wrong with your b-body that a 187 pan that hit the drag link, but there was a problem someplace. I had one and drove it for years.