Oil & filter every 3000 - 6000 miles,
synthetic after engine is broken in. Blow air from inside the air filter out. Check tire pressure.
Spark plugs, check timing every 6000 - 12000 miles.
Fuel filter, air filter, PCV valve and carb douche with Gumout spray every 12000 miles.
Change trans and diff
oil at 12000 miles.
Flush and replace anti-freeze at 12000 miles.
Pull wheels and check brake pads at 12000 miles.
Belts, hoses, and rubber fuel line at 24000 miles.
Granted this is '60's technology with some 21st Century technology thrown in. There really isn't much to maintaining it. You can plainly see the engine. It's not buried under wires and hoses. And it requires maintenance similar to a mid 60's Mustang.
Co worker with late model Corvette was complaining about the high cost of maintenance. $2500 for a "Tune-up", because it has 11 computers in it.
Oil, filter, and plugs for a Cobra with no computers in it is maybe $25. And his Vette takes a healthy whack in depreciation 1) when he drives it off the showroom floor, and 2) every year. Your brand new, 35 year old Cobra doesn't.