Yes, you should be able to tow 8K. The misleading part...an RV trailer normally has a large frontal area, and huge sidewalls. If you are towing a flatbed trailer, with a load of bricks 8K would tow much easier.
You also need to be aware of hitch weight, as an 8K travel trailer may have 1K+ of hitch wt.
Looking to tow a TT with an older 1500 V8 3.73, I'd suggest staying at 7K or less actual ready to camp wt. If you have 4 passengers plus gear and lots in the bed of truck, that needs to be figured in too.
Jerry