What does detonation sound like?

Retard? I thought for detonation you advanced the timing?
No sir. Retard. Or run a higher octane. You can try a step or two or three colder plug. Anything you can do to cool the incoming air charge will also help. Thermoquads are known for being notoriously lean unless they've been modified. Fattening it up may help some. I would be trying a THICK insulator gasket WITH heat shield under the carburetor. Blocking off the exhaust cross over in the intake. Install a high flow 160 degree thermostat. What distributor do you have? What's the initial timing? What's total and when does it STOP advancing? You may need to limit the total mechanical advance. Might be coming in too soon. Lots of things to try.