Nice list of parts!
What are the specs on the cam?
I think the 390 will work pretty good.
I liked the 600 DP Holley.
A set of 3 side drafts makes a huge difference,so consider that upgrade if possible.
I would try your Offy intake & a Clifford intake for a back to back comparisions., No reason to get rid of the Offy just yet.
Your stock HEI should do fine ,just install a spring/weight recurve kit.
Run as much initial timing as possible (as not to detonate) & limit your mechanical advance.
The stock external HEI coil worked fine for me.
I only ran a stock HEI w/an Accel external coil w/an MSD6 box & a timing control box plugged in.
I had run nitrous,& supercharged & 12.1 compression N/A engine @ different times w/that set-up w/no problems.
MBHD
