As I have said before, it's the whole package that works best. A wider gap on the plugs, with a hotter coil should work best. Not just opening the gap. More gap, more fire to burn more fuel, but you need a hot spark. I run a Accel Super coil on my 340 van and give it a little wider gap. I'm sure there is better ways today, but It's been a 45-year set-up and had no issues.