Wondering if anybody has any ideas on how much a 1977 F150 2wd, 460 4v, c6, extra cab , short bed Ranger can tow? Millage is about 90k and in great shape mechanically. Not sure on gears but tires are slightly larger than stock, slightly. Thinking of hauling a trailer that weights in at about 1900 lb empty plus cargo. What do u think?
Thanks.

 

That unit should have no problem with a 1900 lb trailer. If you have a good eqalizer hitch and trailer brakes with a good controler set up right you can start safely adding weight. If you have a low numeric final drive ratio and much larger tires that will be a major limiting factor although the 460 should have plenty of grunt. Be mindful that frontal area of the trailer is also a limiting factor in how much you can tow at road speed.
I would think long before I planned on much over 6 k lbs total trailer weight. The owners manual for my '78 shows recommended max of about 6000lbs trailer weight for a similar vehicle. My 2007 F150 has a trailer capacity of I believe it is 9,000 lbs and I've towed about 6,500 which it handles nicely.
A lot depends on how heavy your truck is sprung. Does it have an any additional transmission cooler? Are the tires up to the load?
Before you go more, consider what I've mentioned so far as additional equipment.

 

I haul a 6,000 pound tractor with my 79 F150 with 302. Engine is slightly built and it has a shift kit and aftermarket tranny cooler. Has trailer brakes and truck has heavy duty spring helpers. Gets 16mpg and loaded it still gets better mpg than a 460. Mileage goes down to about 10 when loaded.