To answer Bills question, voltage does have something to do with it, since the ballast resistor is providing a voltage drop across it before electricity gets to the coil and points. If it were a 6v system already then it wouldnt need a voltage drop. Hopefully that answers the question..whatever the question was. To put 440 valve covers on a 413 is possible, but you will have bolt holes in the corners of the covers and no bolt holes in the head. Find another 413 or an old 361 or any B/RB engine up to 64 (?) and use them. Othewise anticipate a leak around the corners of some degree. Firing order, for the person with the 413 problem with no spark, spark plugs or similar and the subject of firing order came up. It seems that everyone and their dog knows the firing order of the engine....1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 and that number one cyl is the front one on the drivers side, but Id make sure its in the right order on the cap and that its going the right direction COUNTERCLOCKWISE before spending too much time with that one. The fact that there was spark at the plug says the ignition is working, whether or not its getting to the correct plug is another story. Check that and as was suggested, see if theres any fuel getting to the cylinders. Mikey 62 Crown Coupe