what spark plugs for a mild built 340

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chubsgts

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what plugs go you guys think a mild build 68 340 stock 650 carb mild cam elc ing would like to run i have champions in there now not sure if im better running a bosh or any thing else

thanks
 
I've had great luck with NGK's too. Since you didn't change the compression ratio a stock replacement NGK for that engine should work fine.
 
Autolites were the worst....I run a 750 DP high 11 second car. MSD loves NGK and its not even dyno tuned yet.
 
if you are running the correct heat range...the brand of spark plug is not going to matter..

a spark plug just reflects what is going on in your combustion chamber...if you are too rich..the plug will foul no matter what brand it is..

68-71 340s came with N9yc
72-73 340s came with n12yc

find a plug that is close to those heat range and you are good to go..
 
Theres a website to cross ref those plugs to other brands.
 
1970Duster said:
I use Bosch plat 4 no problems ever
Click to expand...

Except the electrode goes away real fast in a heavy service motor....

The higher compression 340's ran the colder plug.... :thumblef:

if you are running the correct heat range...the brand of spark plug is not going to matter..
Click to expand...
:thumblef:



Autolites were the worst....I run a 750 DP high 11 second car. MSD loves NGK and its not even dyno tuned yet.
Click to expand...

Run great in a blown alchy 6 sec olds based car.......
 
dodgetkboy78 said:
Except the electrode goes away real fast in a heavy service motor....

The higher compression 340's ran the colder plug.... :thumblef:

:thumblef:





Run great in a blown alchy 6 sec olds based car.......
Click to expand...


1 thing...Do you drive that 6 sec on the street....Doubt it. I drive mine...
 
NGK...I run them in all my Mopars. I can't complain. The Champions don't seem to be as good as they were once upon a time (like most things)
 
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
 
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
Click to expand...

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.
 
I run NGK's, never had any issues. I'm sure running wise you wouldn't see any diff. between brands. I just think the machining, etc. seems better on the NGK's. I have pulled brand new plugs out of the box with galled threads, crooked electrodes, etc. I work retail and wholesale auto parts so I see a ton of sparks plugs every day. JMO.
 
had noting but problems with champions ill let you know when i fire it i just went to auto parts and they gave me ngks only one listing there
 
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