When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
That's the sound I get when I just get on the throttle, usually in third or four gear when my timing isn't dialed in and I thought it was detonation or pinging. It seems to happen just at that point and more throttle and it goes away.
I know that you and I seem to have similar situations with our 302's.
Fattening up the carb a bit on the throttle pump or a swap of power valves might be a place to tinker. Taking away timing takes away power. If you have a lean condition which can cause detonation, start there before killing horsepower. Excessive engine temps play a part as well. A large part detonation is timing, but there are other smaller players as well.