[XfireZ51]

Jerry,

I have tried .050” on my motor, and it certainly appeared to result in a smoother idle. However, i went back to .035 due to the apparent additional strain the larger gap puts on our ignition coils. The larger gap certainly would help in terms of flame propagation and a better burn, which is one of the reasons I continue to pursue the use of the LSx ignition system on our cars. Increased dwell times and hotter spark have a beneficial effect on a high rpm motor such as ours.
Good to know that Corey finds the NGK 5 heat range is appropriate for the LT5 because its the same conclusion I came to last year and what I have been using since.
BTW, I wrote to Corey asking for his reasoning on his recommended gap and here is a relevant portion of his response.

“Makes more power on the dyno with the bigger gap, and carries the power higher in the rpm range. I wish I could say it's just random reasons why I do the things I do, but unfortunately it's all based on years of testing and experience along with a little physics and engineering thrown in for no reason at all...”

I think Corey is being modest here. Nothing wrong with experience and using an educated guess. Knowing Pete and Marc, I can say I certainly would trust their educated guess above something strictly hypothetical. I also appreciate Corey’s very quick response to my question.