power steering not so easy

My 75 has factory power steering.It has what i believe to be a fairly new ford hd power steering pump.I had some welding done on the truck and when i got it back the steering felt tight.It is fine if you aren't on the go pedal too much but if you are gassing it it really doesn't want to turn .Could this be the pump taking a dump, is it normal or am i really screwed with a messed up box. It will turn easily if you let off the gas at any speed.For what it's worth i have 39.5's to make it worse. I would also appreciate any donor vehicles to get saginaw pumps out of.I have seen write up's but only know to look in country squire 351 waqons. I would like to try a junkyard model before buying the napa upgrade if it is just the pump being the problem. Thanks william in va

I suggest getting a new higher powered pmp and going to a hydro assist system..... similar to that of west texas offroad. I dont think you'd have a problem handling those tires with the new additions...

May want to make sure the belt is not slipping also.<br><br>Paul

Any leaks?<br><br>snake