Not only is that the 4.6L V8, it the old 2-valve 4.6L V8. That's a lot of steel for that engine, which is why they eventually made the 5.4L standard.
I just looked on the Ford Fleet towing guide page, and they only go back to 2002. But the 4.6L was still offered then. In 2002, the 4.6L was only available with the 3.55 axles:
4x2 = 6300 lbs max towing.
4x4 with 16" tires = 6000 lbs max towing
4x4 with 17" tires = 5500 lbs max towing
For an estimated weight of camper you should tow (assuming relatively flat terrain):
Subtract the weight of anything in the truck (passengers and cargo) except for the driver.
For an estimated dry weight, subtract another 1000 lbs, to account for typical options and cargo in the trailer.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller