In my case I had no issues running a gap of .025 but I only spiked as high as like 32 maybe 33# on last tune but didnt have blowout issues. I will say that anytime I had blowout issues a new set of plugs fixed that. Also, my car preferred iridiums over the coppers for some reason. Just always seemed to run like crap and I tried different plugs with protruded tips etc. I'm told you want to run as large of a gap as possible without it blowing out. Of course within reason but I'd start at maybe a larger gap and go from there?

 

Larger gap helps to ignite the fuel better since it is igniting more fuel mixture at same time. The tradeoff is a weaker spark since it is jumping over larger gap. Every car will have a happy median, so each person should find it by experimenting. Start with .019-.020 for tune and as you replace spark plugs, open it up .001 each time. Personally, I'll be happy at .023-.025 and wouldn't go bigger. At this time, I'm on OEM coils, but I will build my own in the future.

 

Its hard for the butt dyno to see a difference of power.. I'd stick to a tight plug gap for high cylinder pressures on ethanol.

To the OP, what is the timing around when you get the blowout?