Help with front crossmember fasteners

[68C10]

I'm installing a '72 disc brake front crossmember on my '68. There are 5 - 1/2" bolts on each side. 3 that go through the bottom flange of the frame and 2 that go through the side of the frame. The two that go through the side (near the top) are VERY tight. They seem to be threading into the side of the frame as I tighten them ... is that right? I did POR15 it so the holes are snug but they seem way too tight.
My other question is about the 2 - 3/8 bolts (per side) that pass through the frame and thread into captive nuts on the crossmember. The two in the rear bolt up great but the frame holes on the front ones don't line up quite right. Has anyone had this problem and what did you do about it? I would just enlarge the holes in the frame but I don't want to through the alignment off. I hope I explained my problem so someone can understand it.
All observations and suggestions gratefully accepted.