need helicoil advice flathead

Did a thread search with no luck........edelbrock heads 8-ba style stripped spark plug thread what diameter size/thread size helicoil do I need to use..........advice appreciated..

 

14mm have used them a few times.

 

I hate it when that happens...........
Yeh, the Offy heads I found required a little helicoil massage in a couple plug holes too. Most auto stores have them for 14mm spark plugs.
Good luck,

 

Maybe this ain't a newa flash but years of racing bikes I learned never take plugs out of aluminum heads when they're hot, it increases the chances of the threads coming out with the plugs, but I know this ain't the only way for the threads to get torn up.