Hot Rods 6v to 12 v conversion

Good morning my Guru's
i've placed a 67 235 I6 into a 49 Chevy 3900 flatbed. rewired complete. and I keep burning up the Ballast Resistor's. no call back form the EZ Wire company Yet. I first replaced the original ballast with a RU10T im looking into getting one with a 8 ohm. any suggestions will be taken

 

67 235? You sure it isn't a 57 235? My guess is that the ballast resistor might be wired directly to ground.

 

im going to have to run the numbers on the block.... the wire from the ignition to the ballast to the + on the coil.

 

The resistance of the resistor needs to be the same as the resistance of the gauges or instruments you are trying to run at 6V. If it isn't, and due to Ohm's Law you will not have a 6V differential across your gauges.

It is a basic voltage divider circuit. See Below.