Big Block Advice Needed

I would pull a head and measure to figure out compression, take a look a the head and see what kind of work has been done. I would consider the other heads if they seem nice.
The RPM intake is probably fine for 4000-6000 rpm.
I would put a solid cam in it with the rocker arms you have.

Here is a smallish solid Lunati cam that shows to be in stock.

Voodoo Solid Flat Tappet Cam - Chrysler 361-440 272/280