[Jerry Warren]

i have a 302 pushing 350HP i have a msd 6a ignition what would be a good spark pug gap im running motor craft plugs SP-420 thanks

 

[1970fastcat]

Knowing your compression ratio is the key to setting plug gap. Have that handy?

 

[Jerry Warren]

10:1 out of a 71 mavrick

 

[1970fastcat]

I would set them around .050. Much higher and you need to tighten the gap up a little.