My turn to ask for help with a Holley.

The blue gaskets are fine. If planning to do any tuning, kill the sticky with a little wd-40.
This is just a rebuild and go?
Check the o-rings on the fuel inlet nead and seats.
Do not use nylon gaskets on the fuel inlet fittings. Use hard fibre or Holley metal ones.

Either of Mike Urich's books covering 4150/60 carbs has good step by step with pictures.

Set the primary throttles so they are shut. Count how many turns in are required to show .020" of the transfer slot, and then .040" write those down. That's the working range. Adjust intial timing, PCV air, etc as needed to adjust idle rather than going outside of that range.

Really the main thing is cleaning out the varnish from old fuel and replacing any deteriorated seals and gaskets. The older parts weren't always made to withstand some of the stuff that's put in fuel since they were made. That's one therory about the rash of power valve failures in the early to mid '70s.