Spark Plug suggestions Please

[Jerry in Shasta]

What spark plug is recommend for a repo Thomas head, 6.7 compression? Mostly local driving.
Thanks
JB

 

[Jim/GA]

This will generate a lot of responses, kind of like asking about which motor oil to use. This is a very charged topic.

Snyder's says use Champion RC12YC plugs (14 mm plug) on the 7:1 compression version of this head that they sell.

YMMV.

 

[glenn in camino]

I have a 7-1 Thomas head on my modified B engine. I'm using Champion RC12YC plugs. It runs strong.