Posted By: ChadP
Right spark plug? - 12/14/14 08:16 PM
After two years of trying to get it tuned, finally took the advice of many here on Moparts and dumped the Edelbrock 750 carb. Engine is mild 440, stock intake and exhaust manifolds, 10 to 1 compression, little more aggressive cam than stock. Put on an Edelbrock 600 carb and new plugs and it's running better than ever. Plugs that were removed are Autolite 85's. All plugs were black (not wet, but black). Does that mean the 750 was running too rich, or is the plug too cold? Before going to different plug, I'll put some miles on the new carb, then pull a plug and look at it. If I need to go to hotter plug, what would you recommend for this engine?
Once I switched the race cars to good ignitions, doing away with the old dual point unassited stock type ignitions, I found that one set of plugs would last a long, long time. Nothing wrong in my book on resuing spark plugs that aren't worn out as long as their cleaned and gapped properly 
I bought a Champion Brand blaster type spark plug cleaner when my airplane spark plugs got to be $16.00 each, that motor had 12 of them and where usually good for 300 to 500 hours before being worn out enough to have to replace them. I had to remove and inspect them on every 50 hour or annual inspection. The FAA authorised A&P mechanic had to approve reusing them so I would remove them and clean and regapped them before he got there 
Those where dual massive gap insulated type spark plugs and part of the FAA regulated items on the airplane so they have to pass inspection to be able to reuse them 
Some of us have to watch what we spend on our toys, some don't 
. no telling how much money i've spent on that stuff.