What battery to get for tractor?

I've got this old Ford model 2000 tractor that I'm trying to get running. Nearest I can tell, it was made in 1963. Here's the problem. I was able to get it to crank, but only with a jump from my Buick. I read that this sucker came with a 6 volt system, which was reinforced by the "6V" printed on the back of the head lamp. But I bought a brand new 6 volt tractor battery and it did absolutely nothing. Then I tried the battery out of our '98 Honda. Also nothing. What do?

Edit: It's also entirely possible that it was converted to a 12 volt system because it looks like it's got an alternator in place of a generator, but I'm no expert.

Look for another 6V battery. It might be two 6V battery in series.

Check on starter or generator for Voltage. Or Google your tractor year and model number and see what it is!2 volts is not healthy for a 6 volt system. So you got to be right on the voltage. Too low a cranking amperage will burn out the starter motor(as one would think too high would burn it out when that is not true) It takes what it needs.

I googled…http://www.tractordata.com/farm-tractors/000/2/5/255-ford-2000.html

if it is a diesel, open the fuel tank cap and take a sniff. It is either the same as your car(gasoline) or it is diesel. Diesel takes 12 volts. But not a little Honda battery. Something much bigger that has more Cold Cranking Amps. So you need somebody with a domestic truck(or buick) to run well connected jumper cables from a running buick. Even then it is iffy especially if the battery is several years old.

My gas 4 cylinder car could start on 500CCA 12 volts
Diesel4cylinder(same engine size) NEEDED 800CCA so I got 1000CCAbattery 12 volts

Matters not if it has a generator or alternator as GEN. Will put out 12 volts and alternators will put out 6 volts if that is what is required.

2 6V batteries in series = 12 volts.

You may also have to depress the clutch for the starter to work.

Was that new tractor battery charged up in the store? If it is a gas tractor, then it should work for it. If battery just got the acid put in and that is all, the battery is dead. It has to be charged up on a charger… Take it back to store and have them charge it up if they did not do that. They have a quick charger that gives you most of your power to the battery (85%) With the vehicle running, it finishes the charge up. Yeah, if headlamps say 6 volt then you most likely have a 6 volt starter. And generator. (so a gasoline tractor.) The tractor battery should have done it.

That old it is 6V.
Did you fully charge the new battery?
If so you need to check the connecting wires and especially the ground wire to the engine/ frame.