You need a bias tire patch and glue.  Because the cords run at different angles versus a radial tire patch.  We used to patch tires that were sketchy back in the day.  But most of them were for farmers. 

This is what you need, besides a grinder to buff the area.
http://www.rematiptop.com/part.php?pid=203&cid=27&sid=11
http://www.rematiptop.com/parts.php?sid=7

For something this old, I would stictly leave it for off road use only.  And tubes in tires off road, isn't a good mix.  And once you air down the stem will fall into the wheel.  Leaving you in a sticky spot.  Unless you put a small hose clamp around the stem.  This will help.