http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0604.htm From the picture you can see that the shaft rotates CCW to open and CW to close as viewed from the engine front. Using that you can tell how to orientate the spring. Heat it over the stove to see how it expands and go from there. I assume you have a counter weight on the front of the shaft


Ed