Have stored the old 65 van for extended periods occasionnly (can never spell that word) over the 47 years I've had it. I would start it once in a while, keep fresh oil in it. After ethanol came in would put Stabil (although that Starbrite stuff is better) in it. Still runs great and the time just sitting didn't really hurt it.
(Have had the van since before multi-viscosity oils used Havoline 30 for years, ethanol, low zinc oil, computers, synthetic oils, radial tires, cell phones still had our rotary dial, 4-track tapes yes, there were 4 track tapes, Muntz made them, used to sell them 8-track tapes, cassette tapes, CD's, MP3's, iPods, iTunes, tv remotes, side lights, CHMSL's, mandatory seat belts, terrorism, 55 mph speed limit, kids. Got it one year after marrying the love of my life, just celebrated our 48th anniversary, in the van).
oops, correction, side lites were required in 68, but the 65 didn't have them obviously