steering housing!

I've stuck my nose under many an early A-body's K-frame, and they all have had steering boxes mounted with three bolts (both manual and power steering)....but remember that these bolts have to screw into something! The "nuts" that these bolts screw into are welded into position on the K-frame where you can't see them easily.

What is a pin bolt? Never heard the expression before! Do you mean "stud?" It is possible that someone at the factory used studs to mount the steering box (for some obscure reason). Maybe he ran out of bolts. Or maybe he discovered that the job was less awkward with studs. Who knows?