hi all : I know this topic has been drawn out, tipped over and probably drowned by now , however, this is my dilema : changed the engine from a 134 to a 172 gas and while doing so converted to a 12 volt negative ground system... that said in the interim the original coil (for the 12v engine) was lost, misplaced or maybe the dog ate it but nontheless it's nowhere to be found. So, I cannot find a resistor inline with the newer wiring we did when converting so I don't know what coil I need to purchase to eliminate any point(s) or other ignition problems due to the wrong coil , etc. Just want the right part the first time !