My dad recently picked me up a Shakespeare X-18 Sierra bow for $40 at a flea market.  It's it pretty decent condition.  My question is, will this bow accept a regular string, ie 4 inches shorter than the length?  It's 52 inches long, so I'm going to get a 48 inch string for it.  I do know it needs to be dacron.

Try to find out what the brace height should be and let that determine your string length.

The brace height for that should be 8"-9" according to Archery Archives.