I have a '72 that I know has the original spring set up. It only has one spring. It does have four holes for the spring end, so you can have different levels of preload. I also have a generic Go Wing that is fairly heavy. My spring is set in the second hole from the rear and it holds the deck lid up OK. Once you start to lower the deck lid it does come down rather quickly and with some force. In any case one spring with the right preload will work.