NGK plugs
 

Tom, Rob, & SYC memebers, Which NGK would you recommend for a fairly stock (I did not build this motor) 325 hp 1968 396. The motor does have a Holley instead of a Q-jet and it also has headers. The motor has a small lope at idle. Thanks, Tim E. Penton, Jr. https://www.yenko.net/ubbthreads/imag...mlins/flag.gif

Re: NGK plugs
 

Would it use the same spark plug (physical dimension-wise) as an 840 head? If so, try an R5671-7...