Hooker headers with Milodon 8ct pan

If you dropped the engine in without the transmission installed, that might be why the oil pan cleared the k-member.

When I first got my a-body with the headers that came with it and installed the pan, I had to beat the heck out of the pan and headers to make it fit where the passenger side flared out. I was in a hurry to get it in to make a race. I changed the headers as soon as I could afterwards. I don't recall if they were Hooker or Headman. But whatever brand you have, like everybody has said, you'll have to heavily modify something or change it. Don't know about trans clearance, mods or tweaks.

Have you checked header/ torsion bar clearance with the block & heads but without the pan.