I loaded 2 Olds 455',2 Buick 455's,a Chevy 283,a truck 4 speed and two T-400's (that's-uh-about 4,000 pounds)in my '57 GMC once,helping a friend clean out a garage,then he found out he didn't have a place to drop 'em,so I hauled 'em around for about 2 weeks. I'm not gonna blame the rear end grenading 9 years later on that particular job. It was probably about 130,000 miles of pulling a 4,900 pound 5th wheel with it.
I'm sure you can haul composte with your truck. try loading a half load and see how it does,if it handles that pretty well,add some more. Might be good to run it across the scales when you reach what you feel is a comfortable limit to see what constitutes an official load.
