please recommend slide bar for 99 Astro Van 250LB tongue wieght

[thebrain]

please recommend slide bar for Astro Van 250LB tongue wieght 2500LB not to exceed 3200LB total load.
I have a 99 Chevy Astro Van conversion I will install the class three hitch today.new boat will require a 2" ball.
I'm not exactly sure of what type of slide bar to get
straigth, elavated or how long it needs to be the reciever is allmost even w/ the rear bumper I attach image (not my Van but same hitch).
I kindof like this dual type http://www.harborfreight.com/1-7-8-eighth-inch-and-2-inch-double-ball-hitch-mount-94900.html
because I also have a 15' boat which is much lighter it's tongue wieght is around 100LBs 1 7/8 ball
I was thinking I could stack 250LBs of my workout wieghts just above the reciever inside the Van to simulate a trailer
then observe how much if any the rear is lowered.
I can upload a image of this.
Van has orginale rear shock absorber and leaf springs,
I was thinking about adding air shocks to lift the Vans rear if the 250LB TW made the Van squawt.
edit I will have a 500LB freezer located in the middle of the Van on my way back from the fishing expedition.
http://www.harborfreight.com/ball-mount-hitch-with-4-inch-drop-94901.html
Will this lock pin hold up to a saltwater envirement?
http://www.harborfreight.com/5-8-eighth-inch-hitch-lock-95831.html
Thanks for any tips on selecting the proper slide bar.TB

 

[oldjeep]

Couple thoughts
1) I like harbor freight as much as the next guy for cheap tools that may or may not break. I'd never buy a receiver there. Get yourself a name brand quality receiver and ball online or from your local auto parts or farm store. Not worth saving $20 if you wind up with something that breaks.

2) You need to do some measuring to figure out your needed drop, or do it the simple way and buy an adjustable hitch.

Cheap steel adjustable - http://www.etrailer.com/Ball-Mounts/...w/MT70067.html
Really good aluminum adjustable (overkill for your load) - http://www.etrailer.com/Ball-Mounts/...en/AM3410.html

3) If your lock pin is getting anywhere near the water you are going to be having bigger issues than a rusty pin.

 

[smokeonthewater]

250 lbs will not sag the back of the van enough to matter..
The drop of the ball mount (not "slide bar") is dependent on the difference between the van and trailer.. Measure each w trailer level and the sure toss some weight in the van.... You don't have to get it exact.... A couple inches either way won't matter but you don't want it WAY off.