Towing Issues: 85 F150 towing Capacity, transmission oil coolers, pound trailer

Question
I have an 85 Ford F150 300 inline six. Can you help with calculating towing capacity or point me to info? Here is all the info on the truck.
300 inline 6,
4x4,
GVWR 6250,
Rear GAWR 3750
Front GAWR 2950
Axel 3.55 ratio,
Transmission C6 3speed auto  

Answer
A VERY generic answer for most 2wd half tons is not exceeding a 5000-7500 pound trailer for properly equipped trucks with a tow package. Since your's is a 4wd, auto.and 6cyl I would think it would be much less maybe around a 3500 pound trailer. There are a lot of other factors such as external transmission/oil coolers and type of hookups (gooseneck, bumper pull or frame mounted weight distributing hitch). Terrain such as mountains or flat roads also makes a huge difference regardless of recommended specifications. Some people miscalculate the cargo/weight that will be loaded in the truck and max out the GVWR and forget about tongue weight. Trailer tongue weight must be added to the GVWR which is a additional 10-20% depending on the trailer and how it's loaded. May not sound like a lot when empty but adds up on a loaded trailer. I also recommend www.fordf150.net for more research.