I would greatly appreciate help with giving me a direction to go in with my model A rear spring. Im going to suicide Z and box the my model A frame but i remember that people on the hamb have used a 40 spring in the rear. I have been searching but i can only come up with one artical but it is not that great. Which spring do you use in the rear with a suicide rear frame? Front or rear spring? Im finally getting back into working on the car again after not working for sometime now. I kept the car thru some bad times but now its time to get back on track. Im new at these types of cars so take it easy on me. Rear is a 65 Mustang 8 inch.