Hi Ken
Well since you asked. I had the same thought while trying to install that spring. I may be crazy but I finally put it in because it showed it in the assy manual. I did not take this car apart, bought it in boxes and completely stripped and decided it was the biggest jigsaw puzzle I will ever do. I researched the spring-not too deeply--and decided the spring was to smooth out the foot pressure on depressing the clutch and limit play in the linkage. Now that I'm thinking about it I will look into it again but my mind wanders back to the older mustang-65 or so-without that helper spring and how the clutch felt like stepping on a plum, at first firm then after an inch of travel soft which is not ideal. Give me a couple of weeks and I will be removing the spring so I can change out the link from the bell crank to the t/o bearing arm I think. Are you assembling , restoring or repairing? Right now I am installing power steering so will slide under and have another look maybe it will rattle my brain. Royston near Comox?
Bob