Marvel Mistery Oil in all the cyl. let it soak then I would try and turn the engine over by hand if she turns drain the oil and change the filter , refill with some 30 wt. and a little marvel get clean gas to the carb ,I use a gas can with a pc. of hose to the pump . just a little gas down the carb and give her a try . check the plugs and the points first as Your soaking the cly's .fill the rad. with water so if there are any leaks it will not matter .
Good luck, Have fun , Pete