If it doesn't knock on 89 run it. My older 250 was running between 13.9 to 15-1 compression and it ran like Hells fire (89) no knock No Ping. And would start with just a bump of the key. But you couldn't shut it off without loading the clutch.
They run much different than a v8 my 396 (12-1) you couldn't get it to start on 89.
God doesn't like ugly.
