41.52 inches spring centers @ measured on rear axle, could that be across the axle to the center of the spring seats? Below is the spring assembly chart. His spring are 3712520. 52” long 26” center to center. The number 2 leaf is 25 ¼” center to center. It looks like 26”. If #2 is not 25 ¼ or #1 is not 26”, I would return them. Check the arch, you will have to remove the spring. Arch 6 5/8”
