Is it a 1/2, 3/4 1 ton truck?
An
average pallet of ceder shingles contains 10-square of cedar.
Average dry weight per square: 160 to 320 lbs. times 10 = 1600 to 3200
Average wet weight per square: 320 to 560 lbs. times 10 = 3200 to 5600
10 square will "fit" into a 6.5' truck body.
The real question is, CAN YOUR TRUCK HANDEL THE WEIGHT!
Without more info, that is the best I can do. hope it helps.