spring rates for 1981 J-trucks --------------------------------------------------- J10 118.7" WB Front / Rear 5 leaf 215 lb/in / 5 leaf 165 lb/in opt: 230 lb/in / 265 lb/in 260 lb/in --------------------------------------------------- J10 130.7" WB Front / Rear 5 leaf 215 lb/in / 5 leaf 245 lb/in opt: 230 lb/in / 265 lb/in 260 lb/in --------------------------------------------------- J20 130.7" WB Front / Rear 7 leaf 260 lb/in / 2 leaf 340 lb/in opt: 330 lb/in / 510 lb/in ---------------------------------------------------