what spark plugs for a mild built 340

chubsgts said

so i took the champion number crossed it to ngk i get three

bp6ey
bp6es
bp7es

what should i buy out of these or a littel more info to help me know the diffrence would help if no one can narrow down a plug

thanks

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I assume you mean you crossed the N9YC over since that's what a 68 340 calls for. In that case I come up with BP6ES. Here's a link to NGK's page that shows plug cross over.

http://www.clubplug.net/champ_ngk.html

You can also use the 5/8 hex plug if you like. The NGK # for it that's the proper heat range is FR5. I have headers on my car and the 5/8 hex sure gives you a lot more room.