I have a stroker 416 ls3 compression its around 11.5/12, I'm running the br7ef NGK on e85, I'm getting some pop through the muffler when converter locks and at WOT i feel some misfire its not getting her full power. I feel that its not liking the spark plug i did some research and they talk about a colder plug 8+. AIrfuel its good i have add fuel and take off and it does the same and i don't think its detonation.
I forgot to get a log but everything looks good on fuel.