here's what I would do.
1, go buy a tune up kit.. spark plugs, points, rotor, cap, condensor, spark plug wires ( more on this later.
2, go buy some cheap walmart atf fluid.. fill each cyl full then loosly thread the old spark plugs back in to keep debri out. let set a day.
3, drain old gas tank if it isn't bone dry already. can do this during the day of setting for the atf. remove plug on the bottom of the carb and add a couple gallons new gas to the tank.. open the gas valve under the tank.. sediment bowl should fill, then gas start peeing out of the bottom of the carb.. put the plug back in and slipt he air hose off.. wat 10-15 minutes and make sure gas does not start leaking out of the carb. if it does.. float may be stuck, needle/seat dirty.. etc.
get a new battery. this machine was originally 6v positive ground and had a generator.. if it still is setup this way go get a new battery.. tractor supply has them.. so does interstate. (1VHD battery number )..
grease up the posts and install, and clean the gornd cable to the chassie connection.. i'd remove and sand and replace.
might already be converted to a 12v battery and negative ground an an alternator. if so.. hook back up that way and get a new battery.
drain engine oil.. make sure there is no water in the old oil.. also check to see that there is fluid in the radiator.
get an oil filter for it.. fram C3 or C3P, or a napa 1010gold
day 2, remove the plugs, roll the engine over by hand half revoloution.. refill with atf rethread the plugs.
new plugs.. champion h10 are oem but most prefer hotter like H12.. autolite 437 are that same heat range.. al 216 ar ethe colder ones. ALC7 is what a dealer will sell you. they make sparks too.
get real metal core plug wires.. even if you have to cut them to fit yourself. tsc sells kits.
fire order is 1-2-4-3 .. #1 is at the radiator
now.. from here.. need to kow if it is a front mount dizzy with 4 wires and a square coil on top .. or a side mount dizzy with 5 wires and a round can coil.
front mount.. take 2 bolts out and remove the dizzt to install and set points. point gap is .015 .. when reinstalling.. spint he rotor with your finger till it slips into the offset groove on the cam then add the 2 bolts... set coil on and flip the bail up and re hook the wire to the coil.
side mount.. set points at .025.. leave it on the tractor
spark plugs gap at .025 on all models.
after 2nd day, remove old plugs and lay some newspaper out and spin engine over by hand.. if it is smooth, then refill engine with oil.. should take about 5 or so quarts, and put a half quart into the air breather cup after cleaning it out... i'd use a 15w40 oil in a mild to cold climate..and see what that gets you for oil pressure.. you can always change it later if it is a tad low... now then spin over a couple cranks with starter.
this will expell al the old atf out.
put in new gapped plugs and hookup plug wires
turn on key and make sure there is power to the coil and gas is turned on, foot on clutch, throttle to mid, start turning her over and then give some tugs on the choke..
here is an exhaustive list of cross over oil filters.. below that is front mount, then side mount ignition parts.
Here is a list of Oil Filters for 8N and other Ford tractors.
Ford Part Number: CPN 6371B 9N-18649, 9N-6714, 9N-2731
Fram C3, C3-P
NAPA Gold 1010
Motorcraft FL 144
Balidwin P40
Big A 92010
Bosch 72127
Carquest 85010
Fleetguard LF574
Wix 51010
Purolater L20110 or L20701
Fleetrite LFR-8574
Texaco HSO-100
Unocal OF 1010
White 10575
Hastings Mighty M3LF-130
Luber-Finer P3
Ignition Parts:
Front Mount distributor...
Points:
NAPA #CS35
Standard Ignition Blue Streak #FD-6769X (Premium)
Condensor:
NAPA #FA200
Standard Ignition #FD-71
Rotor:
NAPA #FA300
Standard Ignition #FD-104
Distributor Cap:
NAPA #FA350
Standard Ignition #FD-126
Side-Mount Distributor: 8n thru 4 cyl thousand series
Points:
NAPA #CS749
NAPA HEAVY DUTY PIERCED (ventilated) #CS753
Standard Ignition #FD-8081
Standard Ignition Blue Streak #FD-8081X (Premium)
Condensor:
NAPA #FA66
Standard Ignition #FD-75
Standard Ignition Blue Streak #FD75X (Premium)
Rotor:
NAPA #FA67
Standard Ignition #FD-108
Distributor Cap:
NAPA #FA352
Standard Ignition #FD-128
side mount points hold down screws #8-32 X 3/16
FORD AUTOMOBILE dealer parts counter. come with built-in lockwasher. p/n 355047-S7 (#8-32 X 0.19)