Is there a difference between the front leaf springs on a 99 and up Super Duty? And is there a difference between the 99 and up F 350 and 250 front spring packs? I need a set for a 99 F350 but they are under a gas engine and I do not know if it is a 2 or 350.

it alll depends on the spring code and if it was a plow package for the leveling everyone wanted x code springs on my 03 I used a set from a reg cab v-8 gasser, they sat level with rear even with the diesel motor when we redid the 00 from being lifted I had a set from a v-8 gasser they had way too much sag and I added a leaf to them short answer it depends on the code and between 250 and 350 they are all 2 leaves

if you have the donor vehicle it is on the sticker This is what I have collected on Ford's front leaf spring codes: S codes = 4000lbs capacity, 370 inch/lbs, 4.34" travel. B codes = 4100lbs capacity, 330 inch/lbs, 5.02" travel. C codes = 4300lbs capacity, 350 inch/lbs, 5.01" travel. T codes = 4400lbs capacity, 390 inch/lbs, 4.63" travel. D codes = 4700lbs capacity, 380 inch/lbs, 5.14" travel. U codes = 4800lbs capacity, 410 inch/lbs, 4.89" travel. V codes = 5200lbs capacity, 430 inch/lbs, 5.13" travel. W codes = 5600lbs capacity, 450 inch/lbs, 5.34" travel. X codes = 6000lbs capacity, 470 inch/lbs, 5.54" travel. Capacity is per set. __________________ if ya have loose springs the part # is stamped on them o R - F81A-5310-AAB, 3,600 lb. o 7 - Six-speed manual, Dana ZF (M6HD-W), o S - F81A-5310-AAB, 4,000 lb. F-Series (diesel) o T - F81A-5310-ABB, 4,400 lb. o U - F81A-5310-ACB, 4,800 lb. o V - F81A-5310-ADB, 5,200 lb. o W - F81A-5310-AEA, 5,600 lb. o X - F81A-5310-AFA, 6,000 lb. o Y - F81A-5310-VA S = 2C34-5310-AAB, 4,000 lb. T = 2C34-5310-ABB, 4,400 lb. U = 2C34-5310-ACB, 4,800 lb. V = 2C34-5310-ADB, 5,200 lb. W = 2C34-5310-AEA, 5,600 lb. X = 2C34-5310-AFA, 6,000 lb. just some of the #s I found quickly