colder plugs

[75valiant]

I was wondering if colder plugs would help the pinging situation. Was driving in the other day with 30 to 31 degrees timing and we floored it from a stop started to spin and go a little sideways but then we had to let off because it started pinging right way. The gas is 92 octane from last fall with stabil in it. It has autolite 65s right now with about 9.7:1 compression. What plug would be the next step colder?

We are planning on mixing a few gallons of AV gas 100LL in with 92 octane so we can turn the timing up a bit to see what it will do without pinging and having to get out of it right away.

[Mean Gene]

I believe a 64 would be a step colder.

[crisser]

How do the plugs color? Last fall? Might try fresh fuel before tuning.