Well you may be correct on the 130* temp, but as I said they worked much better on the 10:1SCR 340/440 cars I ran, NGK 6's (340) and then 7's (440) always came out more or less looking right thats with a good mph tune, perhaps a few sizes over the top on the jets?, but thats how we used to run it back then, a bit on the rich side, the equivalent champs showed a lot different picture and going colder just made them foul on the same tune as with NGK's.