Stroked 340 Spark Plugs

[jimbyr]

Hi all

Just finished my 71 340 rebuild. Went with a Scat stroker kit and Edelbrock RPM Performer heads, air gap intake and Edelbrock 750 cfm carb, TTI headers and full exhaust. Now the motor is 416 cubic inches and compression should be right at 10:1. Question is what spark plugs should I use? The old plugs with the 13/16 hex don't fit in the aluminum heads. Not enough clearance on the side walls to get a socket on them. Obviously have to use plugs with 5/8 hex but which ones

thanks
Jim

 

[js29]

i think i would call summit tec department and ask them

 

[moparleo]

Edelbrock , Summit Racing and Jeg's all recommend the Champion RC12YC sparkplug with the flat gasket seat. Use anti-seize and torque to 10 ft lbs. This plug has a shorter reach and gives you more clearance.

 

[jimbyr]

Thanks Leo

 

[purplehayes]

I have the set up in my 72 Challenger and I am using the champion RC12YC plug and it fires the motor real nice

 

[michael]

The RC12YC is what edelbrock recommends for clearance reasons