Does the recorded map say that the drawing is to scale? It is sounding like it is not. I assume that the map identifies the surveyor who did the work. Is he still alive or is the surveying company still in business? If so, or if you can find out which current surveyor (if any) inherited the prior surveyor's business, you might get access to file notes that would explain the drawing.
I don't remember ever having seen a surveyor's drawing that showed courses to the minute of a degree (60ths) and the distances to hundredths of a foot and were off so much as this drawing would be if the 326 includes the 97 without a note to that effect. And I am confident that I have never seen on a survey a distance that was the sum of a straight-line distance and an arc distance. Admittedly, the scale that shows up above makes it look like the 326' straight line is not long enough in proportion to the 97', so something is off. What is off is not clear to me.