spark plug heat range questions.

so are you saing my 360 magnum with 14 degrees of initial timing and 9:0.1 compression ratio could run on 85 octane fuel and be completley fine?
Because where i live regular gas octane is 85, plus is 87 and premium is 91 octane.
I have read and heard of alot of the 1994 to 2002 dodge trucks with 318 and 360 magnums pinging on 87 octane fuel and they are fuel injected and have computer controlled timing. My engine is carbureted with fairly high initial timing setting. I have always been to afraid to rn 85 or 87 octane fuel in this magnum. Mainly because it has had 91 run thru it all its life. I guess i could try the 85 octane, but my girl friends 2009 chevy cobalt with a 4 banger rattles on the 85 octane fuel. Her cobalt runs better on 87 octane fuel vs the 85 octane fuel. When it has 85 octne fuel in it and you start it up cold it rattles and knocks untill it warms up, but if it has 87 octane fuel in it and you start it up while its cold it doesnt rattle or knock.
so i figured since a 4 banger couldnt handle the 85 octane fuel that my 360 most likely wouldnt like it ether.