The Galen parts book lists the
#315 head as a 64-65 head with 1.78/ 1.50 valves and a closed chamber #080 head as a 64-65 head with 1.78/ 1.50 valves and a closed chamber
#178 head as a 1966 head with 1.78/ 1.50 valves and a closed chamber (early)
#234 head as a 1966 head with 1.78/ 1.50 valves and a closed chamber (late)
#920 head as a 1966 head with 1.87/ 1.50 valves and a closed chamber (273-4 with CAP)
#951 head as a 1966 head with 1.87/ 1.50 valves and a closed chamber (D Dart)
#920 head as a 66-67 273 and 67 318 with 1.78/ 1.50 valves and a closed chamber
In 1968 the 273/318 heads went to a open chamber with the same 1.78/ 1.50 valves
I have a set of #920's but without matching the part number I don't know what they came off of. I doubt if they are the 1.87 intake valve heads.