Coil is a new MSD pro power coil. Ignition wires were replaced, tried 3 different spark plugs. Right now it has 84 and 85 jets. Maybe a bit rich but I wouldn't think it would cause a sneeze back thru the carbs. These carbs were on this car when I bought it in January of 2012.

We never ran any jet bigger than 76. 74to 76 front. Secondary plate opened to approximatey 87 jet, can't remember drill size, this with 426 cubes 12.5 pistons and crane R296 cam. Recently we tried to fire my buddy's 440 and it would backfire through carb and out headers. Found it was a bad msd dist, tried another and fired up and ran great. Don't like electricity or converters because I can't visibly inspect them.