I think I have some of these. I will look and post here what I find. I plan on being at the track all 4 days.
I have 3 extra sets. Part number is 1373719. Fits 400-430. Based on the tags these are the 1967 part number. I test fitted them on a bare 400 block.
Cometic makes multi layer steel head gaskets. The smallest bore size is 4.312. From .027” to .120” thick.