Looking for your advice based on your experience - what do you recommend for spark gap?

> 1926 engine
> Champion X plugs
> "standard engine"
> cast iron pistons
> older rebuild ( a little tired)
> coil ignition (6v battery for the moment - mag not working)

Cheers
Adrian

Pretty much identical setup to mine except it's never been rebuilt. I set the X's gap to whatever the little piece of paper in the Champion box said...it was a different figure to what the Ford book says. My other spark plugs are Lodge types; I just set them to the specs in the book. Typically .03" is about right and is fine for coils on 6V.
No improvement was gained by decreasing the plug gap.

Adrian, I have a '27 standard engine, champ X plugs, cast iron pistons, been awhile since rebuild and run on 6v but do have a mag. I gap my X's at .032, have around 500 miles on them with no problems.
Gordon

Thanks guys, much appreciated.
Cheers
Adrian

Adrian, I have Champion X plugs and a rebuilt mag and run at .035
Nevin.