[joe 1950]

I’ve been using champion H-10 plugs in my flatheads for over 25 years and not just my own cars customers also In my Harley and Willys jeep never a problem but over the years working for the Cadillac dealership for 20 years that Champions don’t work good in G M engines always had problems with the porcelain cracking off AC was the best for GM just my opinion