detonation / knock issue on 340

Updates. Found the carb base plate is cracked. So I’m in search for a good replacement. I did do a compression test. Highest cylinder reading 180 lowest 165. The plugs I just put in 30 miles ago look like this. Guess I’ll continue the work after either I find a replacement base plate or a carb. I’ll follow up once I’m back into it

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What carb is it? If it’s a Holley call BLP or maybe ProForm is still making parts and get a billet plate.