farmall 350 powersteer

[sniperwolf]

the plug that goes into the hyd valve that makes powersteering work what size/long is it

 

[used red MN]

the plug that goes into the hyd valve that makes powersteering work what size/long is it

Not sure what you are talking about. To add PS to a non-PS tractor you need to replace the “Safety Regulator Valve with the one that has flow control for PS, see link.
CNHI F350 Hyd Safety Valve w/ flow control
If you use the left arrow on that page it takes you to the non-PS Safety Valve.
It is up on the hydraulic stack behind the gas tank, see #5 in link.
CNHI F350 Hyd. Valve stack
Edit: Looking closer you should have added this on to your previous thread, would have explained a bit more about where your at. When you open the forum in the second row of selections there is a “Find my threads” button that would have got you there. Secondly, it would be my suggestion you post about this in the Farmall and International forum in the manufacturers section.
The part number for the complete safety valve assembly with the flow regulator is 364841R93. Looks like not to many to be had. Have to search out one on a salvage tractor.