about the spark plugs. I've read conflicting thoughts on whether or not I should remove the sealing ring at the base of the plug so it reaches deeper into the chamber.
Yes, you remove and discard the metal ring washers with a '63-'74 head, see here. Also remove and discard that Champion junk and put in good spark plugs as described in the tune-up parts and technique suggestions in this post (which also contains links to details on the ring washer matter).
