pinging and knocking

[paul guy]

I have done nearly 4000 miles in my 30 mod Town Sedan on a rebuilt motor and it goes great I am really impressed but I cant seem to stop the pinging ang knocking when I want more power like going up a steep hill and I always have to back of. Any suggestions I run a 6.1 head, electronic ignition, weber carby, touring cam, lightened flywheel, slipper bearings. I use high octane fuel I have it retarded about 8 degrees. The motor does not run hot any ideas thanks paul from down under