C3 BB Spark Plug Suggestions?

[Craig C.]

I have a '69 427/390 THM 400 car with original engine and 3964290 cylinder heads (tapered spark plug seat). I am in the process of rebuilding the motor (to more or less stock specs) and would like some suggestions for spark plugs. What are my options?

Thanks in advance,

Craig #32671

[Joe L.]

Re: C3 BB Spark Plug Suggestions?

Craig-----

There are "umpteen" options. My choice would be a Champion RV15YC.

[Dave F.]

Re: C3 BB Spark Plug Suggestions?

Joe - wouldn't AC43N be expected if the car were judged?

[Dave S.]

Re: C3 BB Spark Plug Suggestions?

Dave,
I would suggest an AC plug as well. A 43N is cold for street use (even though it is factory correct) and the "N" is for earlier big block applications. A tapered plug (T) is what is required for this application according to the initial post. I would suggest an AC R45T or R45TS(extended tip)for normal driving. By using the AC plugs you get a serviceable plug that will pass muster on the judging field if necessary.