Power steering top bracket attaches to what???

[OUbesto]

Hey guys I need some help....I have a 1970 C10, 8 cyl 402 with factory PS. I just noticed there was a lot of slack in the PS belt so got to work to adjust it. When I loosened the bolt on top adjustment bracket I noticed the entire bracket slid down away from the engine block. In other words, one side of the bracket was bolted to the PS pump but the other side was not attached to anything!!!! So it was only the bottom bolt/nut that was holding the tension on the PS belt! It appears to me that the top PS adjustment bracket should be bolted into the forward most exhaust header hole, right? There was no bolt in the front most header mounting hole which I assume there was at one time a bolt in that hole that lines up with the PS mounting bracket. Can anyone confirm if my logic is correct? I tried to remove one of the other exhaust manifold bolts to get correct size but they are in there way to good and I didn't want to snap one. There are a 9/16 hex head bolt. Can anyone tell me correct header bolt size (ie 3/8" x coarse thread x length)?

Thanks guys!