I recently extracted some Headman 1 5/8 and installed Hooker 1 3/4 super comps. E-body though and I'm not sure how different the earlier B's are but I know the later B's are pretty much the same as an E. Looking at your pictures, it looks pretty much the same from what I can tell.

At any rate, with the car on stands, I sawzalled out the Headmans, then I had to pull the mount bolts and torque strap and jack the engine up a few inches and the Hookers dropped right in. It was the best header install ever in my experience.

Good luck!