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Ron Gusack · 10-12-2010, 10:45 AM

I get about 20 runs out of a set of plugs and then misfiring starts to happen. Usually it starts above 4,000 rpm. When this happens, I replace the plugs and it's perfect for another 19-25 runs. This has been a problem for me with different engine combos and ignitions. I have resisted spending the cash it takes to buy a 7AL, but do I have a choice?
This is a foot brake bracket car, restricted a little to run low 10.0's. Current engine is a 427 BBC, 13.5:1, Chevy OC aluminum head, HEI with performance module and MSD coil. Timing is locked at 39 and retards to about 36. Plugs are currently NGK B5ES, I've tried B7's and B9's. Over the years I've used MSD 6 stuff, with and without crank trigger, HEI's and Accel dual points. I've used lots of plug brands and racing gasses. Different carbs, intakes, compression ratios etc.

I've been lucky this year because it's happened with enough time for me to do a quick plug change and it hasn't cost me a race yet. I can't deal with this anymore. Do I need to just shell out the beans for a 7 series?

10-12-2010, 10:45 AM	#1
Ron Gusack Member Join Date: Feb 2009 Posts: 244 Likes: 1 Liked 7 Times in 6 Posts	BBC plug life I get about 20 runs out of a set of plugs and then misfiring starts to happen. Usually it starts above 4,000 rpm. When this happens, I replace the plugs and it's perfect for another 19-25 runs. This has been a problem for me with different engine combos and ignitions. I have resisted spending the cash it takes to buy a 7AL, but do I have a choice? This is a foot brake bracket car, restricted a little to run low 10.0's. Current engine is a 427 BBC, 13.5:1, Chevy OC aluminum head, HEI with performance module and MSD coil. Timing is locked at 39 and retards to about 36. Plugs are currently NGK B5ES, I've tried B7's and B9's. Over the years I've used MSD 6 stuff, with and without crank trigger, HEI's and Accel dual points. I've used lots of plug brands and racing gasses. Different carbs, intakes, compression ratios etc. I've been lucky this year because it's happened with enough time for me to do a quick plug change and it hasn't cost me a race yet. I can't deal with this anymore. Do I need to just shell out the beans for a 7 series?