As I remember this truck is 3250 with a full tank of fuel and me sitting in it.... I'm 195 lbs.
It's heavier than that...........
An 86 XtraCab has a 5080 GVW and a 1400 payload (as I look at my 86 brochure)
That leaves an empty weight of 3680 lbs without anybody or anything in it (but full tank)
Gas is 6.2lbs / gallon * 19.3 gallons = 119.7 lbs
or 3560.3 lbs as you run out of gas (not including you)