fowled plugs

quickittyMember

I got a question about the right plugs.
My engine is stroked to 393, mid range cam, nothing wild (hydrolic roller) Estimated at just a hair under 500HP. Quickfuel carb.
I have been fouling plugs every 6 weeks or so and I don't drive that much. But I do let the car sit and idle for a while each weekend.
I have tried leaning out the carb as much as I feel comfortable.
It runs great in the higher rpm range, but as the plugs get loaded up it kicks and spits on the lower range.
Is there a plug I can use that won't foul as easy as the autolites? Should I run a hotter plug than standard?
Any suggestions?

4/3/112:09 PM

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jtpanteraMember

Yes, I spent 2 decades trying to dial in a carb. Finally, I boought an air/fuel gauge that I could observe while driving the car. Best tuning aid ever purchased. Finally, I knew what was really happening and could dial in the carb. My recommendation would be to make that investment first. Otherwise, you are adjusting blind.

4/3/117:41 PM

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noquarterMember

An air/fuel gauge is a very good idea.

Without it, here's my recommendation. Please read:
http://www.tuningmadeeasy.com/.../spark-plug-reading/
It's important to find out if the plug is fouled because it's too cold or because it lives in a too rich environment, of course due to carb adjustment. I think your plugs are fine if they don't look black after high speed run, I think your idle circuit is too rich. And if I'm right and you just put in hotter plugs, you risk burning plugs or something worse at high rpm.

There's a lot details to this, please read my link. Getting it wrong could be costly. The good news is that it might just be turning the idle mixture screws in 1/8. Adjusting that is also on my web page

4/4/113:38 AM

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