A/S did not give a GVWR for any year prior to 1994. Only a dry weight. Your dry weight was 4180 #'s. So load up your trailer and tow it to a scale. In Bend there has to be a truck scale some where in the city or may be Redmond up and down the 97.
There is one listed below which is a trek.
PILOT TRAVEL CENTERS109450 HWY 97CHEMULT, OR 97731
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless at the moment.
1996 Lincoln Mark VIII Diamond Anniversary 4.6L (275hp), 4R70W - 1990 Ford E 150 5.8L, E4OD, 3.55 ____________________________________
Phoenix ~ Yeah it's hot however it's a dry heat!