Sparkplug reccommendation offenhauser heads

[duane stone]

Looking for guidance on the proper spakplug to use on my 59AB with Offenhauser heads, Mallory Ignition, Merc Crank etc. Speedway suggested Champion # 271H10 with 7/16 reach. Do I need a longer reach? I've seen some using an Autolite 437 with 13/16 reach and heat range of 7. WHich one should i use?

 

[Vic Piano]

I use the Autolite 437's in our Flatheads with Offy heads and Autolite 216's in our stock cast-iron head Flatheads.

 

[joe plumber]

I use the 271H10 Champions .

 

[4dFord/SC]

I use Autolite 437's in mine.

 

[Ol' Ron]

I like to use the 1/2 reach power tip plug and counter bore the un used threads witha 45 deg counterbore. I feel this gives beter flame travel. Can't think of the number 12Y something or other.

 

[Walt Dupont--Me.]

Some of these new heads have 3/4in. reach plugs, you want to use all the threads or remove the bottom ones like Ron said. Walt

 

[BillM]

Also a good idea to check for clearance to the exhaust valve which is under the plug.

 

[duane stone]

Thanks guys.....any reccomendations on plug gap with electronic ignition?