Your truck is packing some lead for being a gasser if it weighs 7800lbs empty (my Mega cab diesel came out of the dump empty at 7800lbs and it's much heavier than a Chevy cc gasser by a bunch) and your gvw is even lower than the newer 10klb 2500s.
You can do one of 2 things.
1. Worry about it. There are plenty of fools/tools on this forum to help you worry about it fwiw.
2. Believe the door sticker allows you 2900lbs and call er a day. 3000lb "factory" payload is a good round safe number for a 3/4 ton truck.
And don't worry about hauling anything that you hauled with your old Ford previously.
