I took my car to the local drag strip for test and tune night last night. This was the first run with NGK BPR7EIX plugs, one range colder. The car was missing like crazy. Just wouldn't run, sounded like a carb air floats was stuck. I pulled the air filter and checked the floats, they did fine, no issues. Finally gave up and put the car back on the trailer without making a pass. I pulled the plug wires one at a time and found that I was missing on 2, 3, and 4. So it is not carb related. Pulled the plugs and a friend who stopped by to help asked me when the last time I put new plugs in was, when I told him that they were brand new he was shocked by how dry black fouled they were. And yes, the 260 carbs run pig rich at idle, and it was about 80 degrees.

When I got home I put BPR6EIX plugs in before I even backed off the trailer. Purred like a kitten! I never would have thought one heat range would have made that big a difference. After detonating one engine and blowing a head gasket, probably by detonation, I am skidish, so I have gone to extremes here. The slug that blew the head gasket at Kershaw this summer turned out to have about 42-45 degrees of advance it in. That is probably enough to blow any motor, but I wanted to try the colder plugs as well.

Any ideas or magic you can pass along?

Mike