My 85 with 5.8 l has gvwr of 6600 lbs, registered in the state at 7000. Curb weight is just probably around 3800 lbs. My axle code in the ford handbook is rated as a 5300 lb axle,but the door sticker has it at 3900 lbs. Trucks equiped with semi float axles will have a lower gvwr. says here in my 85 book that the 5.0 liter is capable of having a 7800 lb gcwr with a manual tranny and 373 rear, 11,000 with an auto with 373 or 410s. So if I understand the gcwr as documented in the ford manual, your light weight f250 will actually work to your advantage. Subtract your curb weight (3900 i believe you said) from the gcwr listed above that applies to you, and thats your trailer weight. So if you have an auto with 410s (having an f250 you will more likely than not have 410s, possibly 373s), you can tow legally around 7100 pounds. I think I'm right. Can anyone verify this?