With the 8.25 x 20's your not rated at 24,000. Do you know if your truck has the HD front axle and HD rear springs? I'm pretty sure you have the 15,000 pound Chevrolet Rear since you said it has 10 lug rear and 5 lug front.
Count the number of leaves on the front springs (7?) and measure the width (2.5" or 3").
Count the number of leaves on the rear main pack (should be 10 or 11) and measure the spring width (should be 2.5" or 3").
Also measure the frame from top to bottom right behind the cab at it's tallest area and give me that info as well.
With that info I should be able to help zero in on your real GVW rating.
Mike B
