The answer to this may be hiding somewhere in the threads, but I sure can't suss it out. Also seem to be differing opinions. I'm trying to find a replacement coil for my 51 3/4 ton GMC with a 248 ci engine. The 6 volt coil I found at Napa had the words "no external resister required" Does this mean that there is a resister in the coil and i don't need a ballast resister? (which i took out when i got the truck which the po had put in) Or does it mean I shouldn't use an external resister with a 6V coil? (which i think is true) My simple mind has grasped on to the idea that a ballast resister or an internal resister is needed for a 12V coil to reduce voltage to prevent burning points prematurely. And that a 6 V system does not need to reduce voltage to prevent points burnup. Hence, my confusion; why would a 6V coil need a built in resister and is that the coil i should use or should i find one with no built in resistance? sorry for all the blah blah blah but the more i read the more confused i get.