Classic/Antique Car Repair: fuel level sending unit, gage wire, volt systems

Question
QUESTION: i have a 39 ford deluxe and replaced gas tank and sender.am running stock gages and sender is for stock gage only.it dosent work .ran new wire from gage to unit and its grounded to frame.can ground gage and it goes to full.also am neg ground insted of pos ground.could this be the problem or bad new part,thanks

ANSWER: Why are you neg ground? All Fords 6 volt systems are pos ground. Let me know.
Brad

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QUESTION: i got this car 2mths ago and it was set up this way.the people working on it probly didnt know better,or would be able to jump the battery with a regular car.all other gages work fine.was told by folks i got sender from to do ohms test and got the specs also.just curious of the ground thing.also how would you jump a pos ground car with a neg ground car.thanks jim

Answer
Same way as always, POS to POS and NEG to NEG. You should be able to pull the battery and turn it around. Then polarize the generator like this. Disconnect the field lead from the voltage regulator and touch it momentarily to the B terminal at the regulator. This should reset the polarity in the generator. Now disconnect the gas gage wire at the tank. Turn on the key and measure the voltage at the wire, it should be battery. If there is no voltage the dash unit is probably defective.
Brad