AC Delco R44 spark plugs vs R43

[njsteve]

I wanted to try to find a set of AC Delco R44 plugs as that is the factory plug application for my 1969 350/300 engine. I noticed that the application has been superceded to R43. Correct me if I wrong but isn't that one heat range colder? Should I go ahead with the R43 plugs or hunt down a set of old R44 plugs. It's the original engine, now .030 over, with same compression 10.25 to 1 and the cam from a 350/350hp engine. The engine has 1100 miles on it and runs great with the Autolite plugs. No pings, no rattles on 93 octane premium. (I am putting the AC Plugs in for originality/show purposes) Thanks, NJSteve