I have a photo showing this but not sure how to upload it without a photo host, so a description. Assuming it's the same location as the 1972 Daytona look at the rear rubber mounted cross brace which supports the rear battery
carrier mount. There should be a horizontal tab towards the primary side of the cross brace pointing to the rear of the bike, very close to the rubber mount. The mounting loop of the spring is bolted to that tab again with the spring pointing to the rear.