67 olds 88
#2
No. All power steering boxes aren't the same. You will need a power steering box from a 1965-1970 Oldsmobile B or C body. These Oldsmobiles had the centerlink in front of the power steering box. This is what causes the difficulty fitting dual exhaust. Try RockAuto. I believe they have this part.
#4
Well, actually, you can use other steering boxes but you will need to change the pitman arm to the correct one for your car. Most of the Saginaw boxes will interchange, but be aware that there are internal differences. The biggest difference is the ratio. Most folks want a quicker ratio. Along with the ratio differences are the internal stop differences. For example, Camaro boxes have a quicker ratio, making them a popular swap, but the internal stops are different than on a Cutlass and the result is that the car will turn sharper in one direction than in the other. Finally, the 1980s vintage boxes have metric hose fittings with O-rings instead of the SAE fittings with flares. You can get conversion fittings for this.