madmaxmutt asked for the weight rating on the bars, not the hitch. The "hitch" usually refers to the receiver (semi-permanently attached to the truck), and could be rated to 10,000 lbs, even though the truck is "only" rated for 8000. The spring bars (and the WD head) should each have a label, indicating their own ratings. You should not exceed the ratings of the weakest link.
If 1000/10000 is the rating for your WDH bars and head, great. Don't exceed 8000 lbs truck rating. I just wanted to be sure we are talking about the right thing.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller