Power steering or lack of

[grunex125]

This past summer I swapped engines in my 800 series truck to the 350 Big cam III Cummins, and topped off all the fluids and fired it up, the engine fired up great and of course died but with a little patience we managed to get it running like a top. after running a while I got in and turned the steering wheel and it worked a bit stiff at first and smoothed out pretty good only thing is it puked all the power steering oil right back out the breather cap. From what I read it sounds like air in the system. I've searched the tech manuals here and found nothing for purging the system of air, when I looked at the front of the steering gear case I see a small screwdriver slotted stud with a jam nut. Is this the purge vent with the wrong plug? It's located on the top front of the steering gear cover just in front of the tin mud shield. Also I'm using regular power steering fluid should I be using something else in the 350?
Any help would be appreciated

thanks in advance