FBO's black HEI ignition box

toolmanmike said
How much spark (gap) does it take to light the fire?

If you believe Bewy anything under .065 is a power loser.

For those of us who actually TEST **** like this, .040 is about as wide as you need to go. And that’s on 9.5:1 and lower compression.

Go up in compression (and RPM) and you’ll be closing it up.