I am not an excpert on this but, I believe I read that these tractors came out with a generator and used positive ground, but if you install an altenator you have to switch to negative ground because that is the only way they work. Hooking a battery up wrong with a generator does no damage, just makes them start harder and not run as good. However if you do that with an altenator, it will most likely burn out the diodes. With the negative ground the wire to the distibutor goes on the negative pole of the coil. The starter will run the right direction regardless of which the battery is hooked up.
I hope that helps out. good luck.
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