Spark plugs cross reference (GN1 heads)

[vacuum 6]

Are the Autolite 103s the same heat range as AC-CR43TS?

 

[vacuum 6]

I'm currently use 103s in my GN1 but looks like they might be too cold of a plug for this motor. Looking for a hotter plug.

 

[XXQUICK6XX]

I use 103 for race and 104 for daily driving I think they are hotter plug that is the 104.

Steve

 

[gnxtc2]

I would call Tom at Champion and ask him if you can put a gasketed plug instead of tapered seat plug. A tapered seat plug on a aluminum head will ruin the plug sealing surface of the head.

Billy T.
gnxtc2@aol.com

 

[MSDGN]

I would call Tom at Champion and ask him if you can put a gasketed plug instead of tapered seat plug. A tapered seat plug on a aluminum head will ruin the plug sealing surface of the head.

Billy T.
gnxtc2@aol.com

Really??...I've been using tapered seat plugs (103's...NGK's..etc) for years now on my GN1's(with many...many plug changes) and the plug sealing surface on the heads are fine...

 

[JCotton]

Are the Autolite 103s the same heat range as AC-CR43TS?

The CR43ts's are completely the wrong plug for the aluminum head. They are a much shorter reach than the Autolite 103's. If you want a little hotter plug, use the 104.

 

[ttypewhite]

NGK V-groove FR5 plugs also work well with these heads, and they are priced right.

 

[vacuum 6]

Thanks Jack. That's what Tom said too "use the 104s".

Another question Jack...on a stock head motor the 104s heat range = what AC delco plug (CR43TS)?

 

[XXQUICK6XX]

Walter,
I've used Autolite 23 Colder for race, and daily driving #25 for steel headed motors.

Steve :smile:

 

[vacuum 6]

I would call Tom at Champion and ask him if you can put a gasketed plug instead of tapered seat plug. A tapered seat plug on a aluminum head will ruin the plug sealing surface of the head.

Billy T.
gnxtc2@aol.com

Really the 103s are tapered? Both Jack and Tom recommend the 103s.