Initial Spark Plug Selection: Performance Engine

Hi Folks, Gotta good question for ya. How do you decide on a baseline spark plug to use for a performance engine build. Been having excessive fouling problems and it started me thinking about it. Usually, I start with a stock plug and go from there; maybe up or down based on the build and then read 'em. In this case, I built a late-model 350 SBC w/roller cam, but w/186 ported heads, headers, high comp. pistons Unilite distro, MSD ignition, Victor single plane, blah, blah, blah. The engine's almost new and the carb's jetted right, so this engine is effectively nothing like what it came like from the factory. Does anyone have some serious experience/technique/etc. about determining a starting point for plugs? [I'm not talking about plug reach and threads.] Best Regards, Drink

Reply to
James Drinkwater
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My $.02 - start with a stock heat range or one step colder, do some dyno pulls or drag strip runs, then pull them and have a look.

I think it's kind of an endless loop - timing, jetting, heat ranges... they're all interconnected.

For my race car I just have stayed with one range colder than stock (AC Delco R44s IIRC) and they usually come out looking tan. However, I'm not winning so maybe you should disregard this information. ;)

Ray

Reply to
ray

Are you going to be running alky or gasoline?

Reply to
Don Stauffer in Minnesota

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