detonation / knock issue on 340

Hey all, trying to work out some issues on my 340. has bad detonation / igintion sounding knocking. i did not build or know anything much about the engine. Has a holley carb, mopar performance high rise intake. I've changed plugs, timing, fuel, etc. i noticed that when i spray carb cleaner at the base of the carb to manifold gasket it wants to stall so i'm guessing bad seal/ vacuum leak there. does anyone have any other ideas for me to check where its coming from. its from idle to like 3000 rpm then it goes away and the car runs and sounds like an animal. i did not change the plugs or cap. i got this car from someone that had it on jackstands for 19 years due to a bad trans , never starting it. i got the trans rebuilt and have just started driving and attempting to tune. any help would be greatly appreciated