I am considering replacing my fixed position steering column to a tilt/telescopic unit. ...How tough is this and any ideas what years would be interchangeable. To date I have located a 79 unit, (wrong color of course). I would classify myself as a parts swapper mechanic meaning with no electrical abilities.

Not sure, but I would suspect th 79 should go right in.  Not too tough if you are patient and good with a wrench. Just replaced my 79 as it had a loose joint in it and I wanted a better/tighter one.  If you get the Corvette assembly manual it shows how it all goes together, but it is fairly simple.  first off you drop the center cover under the dash, followed by disconnection the electrical plugs for the headlight dimmer, cruise, ignition, etc.  Then, there are a couple of bolts on the bracket under there and you can drop that.  There is a steering column flange on the firewall that you need to unbolt and then you need to remove the column from the rag joint. This is done by removing the locking cross bolt on the steering column side of the joint.  I would strongly recommend you have the steering wheel and front tires pointed straight ahead so you can align the new column.

My previous reply got lost in cyber-space somewhere...again...

The '77 column is pretty much a one year deal...the other year columns will physically fit, but there are electrical differences, such as the headlight dimmer switch on the turn signal stalk, and cruise, if your car has it. There will be some minor differences in the bracket that attaches to the dash, too.
Why not look for a '77 tilt/tele? That would be a simple bolt-in deal, compared to modifying a different year model column. my .02c

[QUOTE=Adams' Apple]...Why not look for a '77 tilt/tele? That would be a simple bolt-in deal, compared to modifying a different year model column...[/QUOTE]

I just placed a 77 t & t column in a 72 convertible you have to change the electrical connector from the 77 to the 71 or year your replacing. The connectors push out easy. Go to www.corvettefaq.com
Click on Jim Shea's Steering Articles
Click on Corvette Steering Papers
Scroll down to the Tilt & Telescoping Steering Column Section
Download Tilt & Telescoping Column 69-82 Disassembly & Repair Paper #1
This article was a big help. Now the important item that is not explained is where the column bolts up under the dash you will have to make up spacers for between the steering colum mount and the dash. I had to make 1/2" spacers or it would crush the opening in my dash. The 77 collar is a little bigger and when you tighten up the collar cause the collar to crush the bottom of your dash.

Great guys and thanks for the feedback... guess I'll start the hunt for a 77 column