1974? Have a 390 4 barrel carb?
Classic style and one heck of a workhorse.
My Dad bought that year new as a XLT "camper special".. used it to haul a 12ft slide in for many years. He gave it to my oldest brother when he bought a new 1980 F350.. My brother drove it until the bed rotted off then built a nice dump bed for it. Has well over 400K miles on it (can't tell you how many times the odo turned over).. My Nephew now has it but it is in dire need of a complete restoration..
Any way.. If you have the 390 (360 is good but often needs some tweeks to make it really grunt)you have a good pulling engine to work with but I have a feeling your trailer is going to be over the payload of your truck.. That year had a pretty soft suspension, gave a real nice smooth ride but was short on payload..
I would suggest that you find out what the available payload is.. You will need the GVWR (Gross Vehicle Weight Rating) and the curb (empty weight). Subtract the curb weight from the GVWR and the result is your available payload..
Then you need to get your trailer weights like tongue weight and overall weight.. I suspect with the length you are over 7K lbs empty and that would be at least 700 lbs to 1050 lbs on the tongue (tongue is considered as "payload" of the tow vehicle)..
Then you would be adding additional weight on top of that.
Sadly I think you might wish to consider purchasing another newer truck for this and keep your classic 1974 as a show vehicle.. In PA 1974 is eligible for antique plates which saves on registration and insurance, the bad thing about that is you can't us it for towing or hauling..