I had a 1968 VW with the 1600 engine stock single port heads and single solex carb.It had that floating miss that the engine was known for. I did some research and decided to give these a try and at the time there were 12-13 dollars each I bit the bullet and bought some pre-gapped for my engine installed them and the engine started easier, ran smoother, and could take off faster. No more floating miss. I have since learned that due to my engine configuration it was harder for the stock style plugs to fire. I had also tried NGK V powers because I was trying to stay with a standard copper core for the air cooled engine. Bosch stock plugs just didn't work as well either.From my experience if you run high compression, aircooled, or hot engines use Denso Iridium plugs with the 0.4 wire.If you have a stock setup water cooled you might try halo plugs or sonic plugs to save money. I've had good results with those also. Iridium plugs 10-13 each or about 6 each for...