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Author Topic:   What is the correct spark plug to use?
sledgehammer
Member
posted March 18, 2004 06:40 PM
Double hump head gas motor running 50% race gas with 13.5 compresion.

I am not sure what plug number to run with these heads any suggestions would be welcome.

Thanks

joetaylor
Member
posted March 18, 2004 07:18 PM
AC r44T torko 100% werk 4 me

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U LIFT U LOOSE


1970z28
Member
posted March 18, 2004 08:25 PM
run j8c champion never had a problem


Raz_900
Member
posted March 19, 2004 12:01 PM
Which casting heads? My 461's took the gasketed plugs and the 041's take the tapered seat.

I'd think 13.5:1 is a bit high for 104ish octane (50/50 mix). Might wanna run 75/25 race fuel.

Also, I'd think an R44 would either melt, burn a hole through a piston or force less timing to keep from blowing up. I ran Autolite AR 133 or AR134s in the 041 heads with 10:1 and AR 72s in the 461s. The AR 72 was the coldest gasketed race plug Autolite had. I believe the AR72 and AR133 equate to an R42 plug.

Start cold and work up. Too cold a plug will just foul. Too hot a plug and you'll be picking up piston pieces from the oil pan or off the track.

rico 08
Member
posted March 20, 2004 08:00 AM
I'd run a R43,a r44t is a tapered seat plug and won't work on humps.I actually run 44's on my 12 to one 355 with no problems,but i run a little more jet than most.prolly with a leaner idle mixture a 43 wouldn't foul and work ok.


Blackgold
Member
posted March 20, 2004 08:01 PM
I've always run R43 in 12 to 13.5 compression ratio 355s and 406s and have never had any trouble with fouled plugs.


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