Front Pro Coil double adjustable stock mount shock kit. Compressed length of 9.63" and extended length of 14.5". Includes 10" spring with rating of 600. QA1 now has GM Pro Coil Systems available for your 1963-1965 Buick Riviera. They offer fully adjustable ride height and valving control. Pick your spring rate and adjustability to fit your driving style, adjust the valving to match and you are on your way. They also utilize a fully threaded body that allows you to adjust your ride height for the perfect stance or to finely tune the weight balance for superior handling.