I've got one that has laid here in the yard for I forget how many years, at least 15. Sometimes 2 years between starts. The only fuel line is a 4 foot hose attached to the pump.
I'll throw a battery and a gas can at it, remove the coil wire and turn it over.
Eventually the 2brl carb bowl will overflow because the float is stuck.
I tap on the bowl with a screw driver handle and try again. Now that float is working, coil wire attached and fire it up. After 20 to 30 minutes of running, everything seems fine, I pull the fuel line and let it run out of gas. Walk away till next time I take notion to fire it up. I have changed its oil and replaced about 50% of its antifreeze 2 or 3 times over the years.
If this was a newer engine that I had a lot of money invested in it would be started monthly and taken better care of. I drive my 67 at least once per month. I cant testify that better care is absolutely necessary though. This 68 engine apparently doesn't require any loving care. LOL
Our 73 didn't either. I would let that Valiant lay in the yard untouched for 2 years or more then put a tag and insurance on it and drive it a year or 2. That car was finally laid to rest at 306K miles.
BTW, last spring, when I pulled that coil wire on the 68 I found oil leaking from the coil. Replaced coil and wire, then proceeded to fire it up.