1963 pickup bed GVW and GVR

[LuckyLightning]

Does anyone have any experience in taking the back end of a 1963 (or 60-66) bed and chopping the frame to convert it to a trailer? I need to register mine (truck was wrecked, only way to salvage it) and am having trouble deciphering the what's depicted in the owners manual.

It's a 2wd shorty, and in the manual it says rear axle capacity is 3500 but rear spring capacity is 2500. That doesn't make much sense to me as I need to know what it's carrying capacity is, which I'm assuming should be the lower number of 2500... does that sound right?

Also, the weight of the vehicle as a whole was either 4100 or 4400 (both numbers are in the same box), but with only the bed and half the frame and rear axle, I don't know what the weight of only those would be.

So if anyone has any experience with this kind of conversion, and then registering it (the important part), I would love to hear from ya as to what all you've filled in the blanks with on the registration form.