Thanks to everyone for the information. I started out using Fox Standard Long plugs, but have recently switched to OS A3 plugs. I was told that they are a better quality plug. When I expressed concern over the difference in length of the A3 and the Fox STD Long, I was told that either one will work. That is where I began to get a little confused. BTW, I am running these plugs in .40-.46 2-cycle engines. What is the difference between the OS A3 and the OS 8 plugs other than the 8 is more expensive? John, I would greatly appreciate it if you can find out for sure which issue that article on glow plug selection was in. I would like to read it. Thanks again to everyone who took the time to respond to my inquiry. It's great to have have a resource like RC Universe to turn to.