Spark plug gap ?

[434nova]

What kind of spark plug gap should I have ? Motor is 235 ci , has gn1 heads ,206 roller cam , te45a turbo , 25 #s of boost , alky kit , and im on 93 octane. Also what brand plug do you guys recommend for my combo with my gn1 heads. Part number on plugs please. Thanks

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[gtfrede]

I use a tight .025 gap with br6fs ngk's but Im not sure what style seat the GN1 heads take but I would always use ngk's....I know some may chime in and say autolite's of some sort which is a excellent plug I hear but I have no experience with them. I just prefer a colder non-progected tip plug design from whoever manufacture but Im partial to ngk.

 

[Flyin Brian]

I think gap also depends on your ignition system and the condition it is in. If you have a high powered aftermarket ignition system you can open the gap up a bit.
I have a new stock ignition with 10 mm Magnecore wires and a volt booster. I am running crappy AC Delco plugs on stock heads with .032" gap and 25 psi boost on E85 without issues. Every car is different.

 

[pacecarta]

with gn1 alum heads you can run taper or gasket seal 14mm x .75 plugs
AR3934 put them in as they come out of box
they are gasket seal non projected tip with cut back electrode and are approx .025 gap and gapping them is not recommended
http://www.summitracing.com/parts/frm-ar3934

the AR3933 would be one step colder
heat ranges are available from the hottest ar3935 (which is a midrange plug) to really cold AR3831

 

[gtfrede]

PACECARTA....is there a plug that is like the ones you posted from summit that will work with stock style irons?

 

[pacecarta]

the AR133 but for me it was too cold to drive around on
im running the junk delco r42ts plugs

 

[turbogn_231]

Any problems running a Non-Resistor plug like the AR133?