My 95 F150 All Set Up For Towing And All Its Had Done To It Was The Stiffer Leafs And An Extra Overload Leaf And Air Shocks.
I Don't See Why You Couldn't Just Use Stiffer Leafs But I Would Look At Putting Air Shocks On It Also. We Had A 5,000 Lbs Van We Towed To The Crusher And My Truck Didn't Squat Hardly At All. Then Just For The Heck Of It We Hooked It To A Friends Chevy And The Bumper Drug The Ground.
"Flyin High On Caffine And Copenhagen" R.I.P Chris LeDoux
60 Mercury Comet
65 Ford Econoline
72 Ford F100 on 79 4x4 SWB frame
77 Ford F250 "lowboy" 4x4
09 Harley Xl1200c
I doubt a 69 f150 would have much trouble towing 5000 lbs, good tires with mechanically sound springs and bushings should be fine. at most an add on overload spring ie helwigs. Newer "1/2" tons are sedans w/ big open trunks