Got an 8N that hadn’t been started in 6-7 years. Flushed gas tank, cleaned sediment bowl (rep
Lace screen and gasket. Cleaned carb put jumper cables on battery, ran very good but turned over slow. Today battery dead. Buddy says go with 8 volt battery and nothing else electrical needs to be changed?? Sorry for being so long winded. Thanks.

My 640 is still 6V and gen.
I jump it with 12V all the time.

Converted my cub to 12 from 6, made life easier.
Had the parts and bat on stock.

It's not too expensive , and it's easy to install a 12V conversion with parts to eliminate the ignition points. Probably less then trying to find an 8V battery.

Starter could potentially be bad from sitting, corrosion inside causing to to crank slowly Also I'm sure you have but check battery connections for corrosion.

8n fords are know for slow cranking, 8 volt batteries can be found but they’re getting rare, the next problem is getting it to fit under the hood though the hole, personally I’d stick with 6 volt it’s just easier.

Eight volt battery is a great farm fix, but it is not necessary. The biggest cause of no start with a six volt system is dirty wire connections. They need to be maintained more often that 12 volt systems. Bright clean metal on all wire ends. Clean bright metal on the block where the ground wire goes, and the terminals on the mechanical starter switch, and the starter terminal.

I've spent several hours on an 8 N.mowing and plowing snow.

It had a 6 volt battery.
I cannot find anywhere that 8N ever had 8 volt battery
just.

You need what's called a group 1 8v. Remember a "dead" 8v is worse than a 6v. You need to increase the voltage regulator to charge at a higher rate. Screw under the cover. I would just convert to 12v myself. They used to make a battery that started on 12v then dropped back to 6v to run. No need to change bulbs and things. Showing my age.

Group1 8volt

I would charge the battery and then load test it.

Converted my 1956 , 871 power master ford tractor to 12volt years ago.

It didn't. 8 and 12 volts are upgrades.

But you can keep the 6 volt guts on the tractor when you go to 8 volt cant you?

Yes that’s what I’m told.

The 8v battery wasn't an upgrade, it was a sorta fix for a poorly maintained 6v system, the extra voltage of the 8v battery overcame to some extent a weak system.

So, sorta like an upgrade, but not really.
I just knew (or was mostly sure) that the 8N was never manufactured with the 8 volt system.

I have a 1950 Chevrolet pickup converted to 12 volts. It still has the six volt starter. That 6 volt starter fed on 12 volts turns that engine over well I can drive the truck across a parking lot with the ignition off. 1950 EV, baby!
You have to change all of the light bulbs when you do the 12 volt conversion. You also need to go with a 12 volt generator, or an alternator.