Possessed power steering

[TC]

Yup... freaking possessed.
I don't know what's wrong, but I hooked up my stock pump on my 5.0 conversion and when I started the engine, the wheel started turning to the left by itself.
I try to stop it, and the wheel jerks out of my hand. I can't stop the SOB and it jams so hard to the left that the steering box starts to smoke.
All of this within a matter of 5 seconds.

I shut off the engine and it won't turn back right.
I unhook the PS belt... still won't turn back.
I undo the PS fluid lines... after some hard cranking I get the tires back straight.

Any ideas?
I'm thinking it might not be the pump, but a stuck valve in the steering box?

help

[Nobody]

are the lines reversed?

[Rockcrawler]

your steering box is blowing by fluid into the cylender to push it one way. You probalby need a new steering box.

[TC]

Not reversed lines.
One is threaded and the other is slip on.
I'll dig into the steering box and take a look.
Anything I need to know?

[mccutcheon4]

One is threaded, and one is slip on, at the the pump, but what about at the steering box itself. As I remember, they are both threaded and could be reversed.

[TC]

Rockcrawler could be right. Unfortunately I will never know. I took off the box. Used an air compressor to put pressure into the stem that the hydraulic line plugs into and almost got knocked out by the pitman arm. Something is stuck in there.
Before I got back from the bathroom my old man had it half torn apart and a bunch of bearings on the table...
I'm in the "want to buy" section for a steering unit.