AFR Headed guys, Spark plugs?
10-03-2009, 08:02 PM
#23
Here ya go. I have used this chart for my AFR heads for a long while. These are the gasket style plugs.
Heat range //////////////////////////// NGK ////////////////////////// Autolite
stock heat(5)10.5:1 compression n/a...2382 ..............................AR3937
1 cold (6) 11.5:1 compression n/a.....5553 (BKR6E)...................AR3936
2 cold (7) 12.5:1 compression n/a.....4091..............................AR3935
3 cold (8) 150 shot.........................4554 (R5671A-8)..............AR3934
4 cold (9) 150-250 shot..................5238 (R5671A-9)...............AR3933
5 cold (10) 300 shot........................5820 (R5671A-10).............AR3932
6 cold (11) 350+shot.........................?................ .................. AR3931
I have been around 12.5:1 compression so I would use a 7 for n/a then colder per size shot I used. You guys with less compression need to scale back one size or two.....meaning if you are 10.5:1 compression use the 5 heat range for n/a and a 6 or 7 for nitrous.....etc.
Good luck!
Heat range //////////////////////////// NGK ////////////////////////// Autolite
stock heat(5)10.5:1 compression n/a...2382 ..............................AR3937
1 cold (6) 11.5:1 compression n/a.....5553 (BKR6E)...................AR3936
2 cold (7) 12.5:1 compression n/a.....4091..............................AR3935
3 cold (8) 150 shot.........................4554 (R5671A-8)..............AR3934
4 cold (9) 150-250 shot..................5238 (R5671A-9)...............AR3933
5 cold (10) 300 shot........................5820 (R5671A-10).............AR3932
6 cold (11) 350+shot.........................?................ .................. AR3931
I have been around 12.5:1 compression so I would use a 7 for n/a then colder per size shot I used. You guys with less compression need to scale back one size or two.....meaning if you are 10.5:1 compression use the 5 heat range for n/a and a 6 or 7 for nitrous.....etc.
Good luck!
Last edited by Tony Shepherd; 10-03-2009 at 08:07 PM.
10-07-2009, 12:29 PM
#26
Here ya go. I have used this chart for my AFR heads for a long while. These are the gasket style plugs.
Heat range //////////////////////////// NGK ////////////////////////// Autolite
stock heat(5)10.5:1 compression n/a...2382 ..............................AR3937
1 cold (6) 11.5:1 compression n/a.....5553 (BKR6E)...................AR3936
2 cold (7) 12.5:1 compression n/a.....4091..............................AR3935
3 cold (8) 150 shot.........................4554 (R5671A-8)..............AR3934
4 cold (9) 150-250 shot..................5238 (R5671A-9)...............AR3933
5 cold (10) 300 shot........................5820 (R5671A-10).............AR3932
6 cold (11) 350+shot.........................?................ .................. AR3931
I have been around 12.5:1 compression so I would use a 7 for n/a then colder per size shot I used. You guys with less compression need to scale back one size or two.....meaning if you are 10.5:1 compression use the 5 heat range for n/a and a 6 or 7 for nitrous.....etc.
Good luck!
Heat range //////////////////////////// NGK ////////////////////////// Autolite
stock heat(5)10.5:1 compression n/a...2382 ..............................AR3937
1 cold (6) 11.5:1 compression n/a.....5553 (BKR6E)...................AR3936
2 cold (7) 12.5:1 compression n/a.....4091..............................AR3935
3 cold (8) 150 shot.........................4554 (R5671A-8)..............AR3934
4 cold (9) 150-250 shot..................5238 (R5671A-9)...............AR3933
5 cold (10) 300 shot........................5820 (R5671A-10).............AR3932
6 cold (11) 350+shot.........................?................ .................. AR3931
I have been around 12.5:1 compression so I would use a 7 for n/a then colder per size shot I used. You guys with less compression need to scale back one size or two.....meaning if you are 10.5:1 compression use the 5 heat range for n/a and a 6 or 7 for nitrous.....etc.
Good luck!
04-12-2012, 06:17 PM
#29
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Reviving this old thread
I pulled TR6's out of my AFR heads - shop put them in and they should have used gasket-ed!
AFR says to start with 3910's but should I really just put in 3937?
I have a about 350-400HP NA.
Need to buy plugs for this weekend so is it 3910 cold-*** from AFR website, or 3937 like you guys say?
I pulled TR6's out of my AFR heads - shop put them in and they should have used gasket-ed!
AFR says to start with 3910's but should I really just put in 3937?
I have a about 350-400HP NA.
Need to buy plugs for this weekend so is it 3910 cold-*** from AFR website, or 3937 like you guys say?
04-13-2012, 12:01 PM
#32
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Ok one more question
does it matter taper or gasket - on how the head is cut? AFR said it doesn't matter if the head is cut flat or taper, that either gasket or taper plug will fit.
I'm so confused.
I'm going to go look at the head now and see what the plug hole looks like.
does it matter taper or gasket - on how the head is cut? AFR said it doesn't matter if the head is cut flat or taper, that either gasket or taper plug will fit.
I'm so confused.
I'm going to go look at the head now and see what the plug hole looks like.
04-14-2012, 05:56 PM
#35
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Well that would shroud the plug, given of course without looking at one installed that it is set back deeper in the hole (or shallower in this case...lol)
