The Classic Performance website has instructions
for a GM steering column installation. They suggest cutting the steering column shaft down to 31 1/4 inches. Can anyone tell me Why? Also, how tough is it to get the steering column
shaft out of the steering column?

Smoran - the shortened shaft allows room for mounting the power steering box. The CPP site also has a tech page, with step-by-step instructions for this installation, which allows you to use the more or less stock (now shortened) column with the power steering assist. Check this out:
http://www.classicperform.com/tech_...ri-five-605.htm
Good luck.

Thanks a bunch! I went to the tech article and if I shorten my column, I'll need the reference. If I don't put power steering in my PU, do I need to shorten the collumn? I assume not if the present column linkage clears the manifold.

You've got it! Good luck with the install, smoran. Don't hesitate to use this forum again in case of difficulties.