The bow is an oldie. What is written on the bow? Typically the length of the bow is written on it someplace along with the weight. Because of the age of the bow, you'll want to check it out yourself, or if you don't know what to look for, have someone that's qualified (not a compound shop, they don't know jack about sticks) check it out for twisted limbs and any signs of delamination. If it's starting to come apart, it's best to hang it on the wall.
The length is either 62" or in the years 69-70 I believe that it was 66" long. Make sure there are no cracks in the riser or in the limb tips.
Once you determine the length of the bow and have made sure that it's solid enough to shoot, then contact a string maker and get yourself a Dacron B-50 string for it. I'm partial to a tri-color flemish twist string, but an endless loop is just as good. Just not as cool looking.

Do not use a fastflight or other high performance string on the bow. They will literally saw the tips off of the old bows.
If you want the name of a good string maker, Chad of Champion Strings makes all my strings for me. He's one of the best and his prices are decent. His site is
HERE, go to it and shoot him an email when you're ready for a string.
Typically it depends on the type of a bow, but a good place to start with the brace height is 7-7 1/2 on a recurve. Once the string is shot in, then it'll need to be twisted to shorten it again as the string will stretch. Measure from the deepest part of the grip to the string for the BH.