Autolite AR3934 plugs

What is the safe limit for this plug in a 472 with Diamond flat tops and out of the box SCJ heads ? I've tried a 180 shot so far (72n-64f jetting in a zex perimeter plate and it seemed ok , just wondering if i'm pushing my luck and should switch to the ar3932 plugs ? Also i'm still running a little fat seeing how i'm just tapping off my fuel line to the carb which has pressure about 7. I am setting up a dedicated cell,pump and regulator for the fuel solenoid but its not complete yet.

3933 for up to around 250-300 will work okay and then the 3932 with more power. If you are new to tuning nitrous I highly recommend the ngk plug first.

Thanks for the info , so the 3934 is safe for what i'm doing then , was very tempted to try a 210 shot this Wednesday TNT for a grudge race that's lined up but think i'll be ok with a 180 , not real comfortable tapping off my fuel line , at least not being able to set the fuel pressure for the nos. Its a 1/8 mile N/T race even tho our track is 1/4 , you can get a N/T card for a extra $10 which is for 1/8 only , This is only the second time doing the N/T grudge thing , i usually only bracket race but this is kinda neat.

To be easier to see the tune I'd move a little colder. Fuel pressure is fine just lower the fuel jet

I'll try the 3933 then or move to the ngk plug , and how much roughly should i drop on the fuel jet to start ?

Take a picture of the plug and I'll help the best I can

x2 on the NGK to figure out the tuneup. You'll burn a piston before an Autolite plug.

BUT.....an Autolite plug WILL make more power

Well i tried it last night and it ran good but he beat me , not sure how much their spraying but it was a close race , the second pass i added one degree of timing , so 6 out instead of 7 from 30 total and that 1 degree made it pop, pop,pop going down the track , i figured it might make a little more advancing it 1 but it slowed up, now i wonder if taking one out for 8 retarded would pick it up some. It must be on the fine line because 7 degrees out it ran and sounded perfect. The plugs were white finally going to 73n 62f jets vs. the 72n 64f i had in it last time left the plugs tan like a good NA tune. Now i'm tempted to try a 82n 72f jet The best ever was a 5.96 @ 114mph with the 72n 64f jetting but it was a cool great night , last night it ran 6.10 with the 73n 62f tune but it was muggy out. I'll post pics of the plugs.

   

hmm, sorry to be a dumbass, but which ngk plug would you start with? thanks bob

zbob wrote:hmm, sorry to be a dumbass, but which ngk plug would you start with? thanks bob

5820 ngk

yellowhorse7 wrote:x2 on the NGK to figure out the tuneup. You'll burn a piston before an Autolite plug.

BUT.....an Autolite plug WILL make more power

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