The only thing plug gap differences affect is the minimum firing voltage with clean, new spark plugs. 40-45 thousandths will produce a spark somewhere in the 10-12 KV range, compared to 8-10 KV with an .035" gap. That's why "40,000 volt" coils are so ridiculous- - - - -that's open circuit voltage capacity which has nothing to do with real world ignition system operation. 40 KV or more would fire plugs with the ground electrodes completely cut off! They just might miss a little under hard acceleration.
Jerry
