pull the spark plugs.. put in neutral.. block clutch.. see if it will roll over by hand.
if not seized.. put some atf fluid in each cyl.
clean or repalce plugs.. champion h10 or h12 ( 512 ).. or al 437 plugs fine.
.025 gap on plugs
clean and regap points ( .025 as well )
roll engine over a bit and add more atf.
get a battery.. same as the old one.. clean up bat terminals and grounds. mae sure you install same polarity.
check coolant and engine oil and rans oil and rear end oil.
once you get it started.. I'd dran and flush all ols and change.
i like a 15w40 oil in the crankcase..and for the trans and diffy.. you can use a 80w90 oil, or UTF.. and for hte hyds, UTF.
grease all fittings.. oil dizzy oiler same with generator if it has one..
service the oil bath air cleaner.
lube the steering box after assessing thrust and sector play.
fo-19 service manual and a master parts catalog is a good 40$ investment.