Lighter springs my be a challenge. Full-size Bronco springs may be lighter, but I doubt it would be much difference. Early Bronco springs are probably lighter. Data seems to be difficult to find for springs. I've always fpund it challenging to make good campoarisons. You need to pay attention to the weight rating - how many pounds it takes to compress the spring 1 inch, and also the free height and number of turns in the coil. Then, to further complicate matters, some springs have dual ratings. They are softer to certain point, then stiffen up. Check Jeffs Bronco Graveyard.