Just got my brothers 460 running & trying to break in the cam, but as soon as the engine starts the steering goes to full RH lock with no input from us. This is a 72 highboy w/steering conversion but the 78-79 control valve housing has been replaced with a '70 2wd unit so things might be wierd. We had a retired ford mechanic who spent a lifetime working on these trucks put it together & he didn't think anything of mixing parts.
I'm wondering if some passage ways may be misaligned or if the parts are incompatible (physically they bolt together just fine) .
Is anyone familiar with the inner intracasies of these steering gears?

 

Only Power Assist P/S has a control valve, but no year 2WD or 1978/79 has Power Assist.

Power Assist: Two long power steering hoses, pressure and return, route from the pump to the control valve.

Two short power steering hoses, pressure and return, route from the control valve to the ram cylinder.

Power Assist: 1973/75 F100 4WD / 1975 F150 4WD // 1973/76 F250 4WD / 1977 F250 4WD before serial number Y20,001.

 

The control valve housing as labeled in the picture below is off of a1970 2wd and attaches with 4 bolts and the power steering box is off of a 1978 f250 4wd.

 

You have your high pressure line in the wrong hole... (that's what she said)
Take a picture of the set-up, but it does sound like you have a routing problem, when it starts, you get high pressure from pump going to the right turn valve,,,

 

Well I'm afraid I dont't have a picture of the setup, but there are only two ports for the lines to go into. the larger port is the return and the smaller port is the pressure. Whatever is messed up must be internal. I don't like tearing into these because I always go to far and then the ball bearing fall out and don't want to go back in and it ends up being a mess.

 

You could try calling Redhead Steering Gears. They rebuild these for a living so might be able to help you out. At the very least, they would sell you a replacement box.

 

That could be an expensive phone call...

 

Well, my brother found a solution to the problem. Never did find the problem, but found a solution...