Currently I'm using the autolites. Changed my plugs and all the plugs were black. This is the first time all the plugs matched. In the past the front were white/grey and the back were black. Currently running a stock carb. Engine is stock with the exception of the stage 5 cast iron heads. Runs a little rich around town but on the highway its fine. I have a problem with pre ignition wide open. Billy Atwood has been helping with this issue. It's gotten alot better since his hands have touched it. Any thoughts would be great. Jimmy

Shiny black is oil and flat black would be rich

Your in good hands with Billy in my book
Detonation could be poor fuel or too much timing or a hot spot in the chamber ie a burnt valve or a burr or carbon deposit acting like a glow plug

Check your mechanicals first.....good luck

thanks for some info to think about. will have some things to talk about with billy atwood.