i did this conversion a few years ago. you can use the power steering intermediate shaft, it is too long and will need cut down. what i did was i bought a u-joint from speedway motors out of lincoln, ne, cut the shaft down, and welded the u-joint on. works well and there is plenty of clearance for the headers, assuming you have a 302 car. i don't remember the spline count, but one end is 3/4" smooth bore, and i had to turn the shaft down to fit. i will try to get a picture up of it either sometime later tonight or tomorrow morning so you can see what i am talking about.
whoa sounds like to much work. Trying to get this sorted out. New 347 in car but is not driveable. Put in a manual rack to gain clearence for oil pan. Stock mustang II oil pan does not clear stud girdle. There is a difference in length between the steering shaft as well ? ( manual vs. power) I can make a flaming river kit work but its $$$. With the rag joint eliminated is there more vibration transfered to the steering wheel ?
Speedway also sells a joint that has the rubber dampening in it aswell. It is a Doubble-D config, so I'm not sure if it's do the trick or not. http://www.speedwaymotors.com/p/2036,297_Inline-Vibration-Dampeners.html
If you cruise under the street rod parts and under steering, you'll find there is alot more stuff you might be able to use. Don't forget to look through the Sprint car stuff too.
You can get that factory steering piece out of any Mustang II, Pinto, or Bobcat as long as they have manual steering. I've found that there are more Pintos and Bobcats with manual steering that Mustang IIs. Shouldn't be too hard to find.
here is the pic of mine-not a great pic, but i think we all understand why....
as far as vibration goes, i dont notice anything unusual. if i remember right, my rack is out of a pinto, and the rack's shaft is about 2" longer. i didn't have the intermediate shaft, so this is why i choose this route. it really isn't too bad, the hardest part would be getting the end of the shaft turned down. only other thing i did was i had the engine out when i did it. dont know if you would necessarily have the room to measure and install with it in there.