Re: Oil pressure switches.
My caveat is at the end of post # 15 starting with " In the end..................."
Like I said it was something I was thinking about.
Re: cooling system.
Over the years GM had many variations of their cooling system but the basic theory is the same. Hot coolant out; cooler coolant in.

 

I'm at the point of trying to source the correct adapter for the temp sender. NAPA no longer carries pn 710-1541 (for 3/8"). I'm thinking of throwing in the towel and installing a new aftermarket gauge.
Any other options out there?

edit: Yes there is an option; was ordering down-pipe from Suncoast and noticed they had the adapter. Done.

Next issues: AC switch, expansion valve, accumulator mount and overflow tank.