The tilt column install is plug and play. I have used columns from an 87 Blazer and 88 Suburbaban. I am not sure the cut off on what you can use but I know those two work just fine. Yes, the ignition switch is configured different for a tilt but the wire plugs are the same, you just flip them over (the one that goes closest to the wheel on the straight column will go on the floor side on the tilt, and is flipped over. Look at the two switches, flip them around and you will see that the pins match your plugs).
Keep the little control box for the delayed wipers! If you don't, your wipers will not work right, if at all (I discovered this AFTER the install and during a heavy rain. Thank you Rain Ex for saving me!). The switch is different and the harness in the column has more wires in it than a non delay wiper switch and harness. The box has an output that uses the same number of wires as the non delay system so everything from the output of the delay box is the same (the dash harness plug is the same for delay and non delay. Wiper motor is the same as well).
If you swap one out, go ahead and rebuild it while it is out. You have four bolts that keep the tilt tight. They are typically lose. The switches and turn signal guts will run you about $50 to replace. The only real special tools you need are the wheel puller and the tool to get the keeper ring from the metal plate on top of the column. You can use some small bolts and a socket or wrench as a puller to get the plugs out that hold the top of the column into the bottom. Do a search on the web for GM tilt column rebuild. The old ones back to 1969 are pretty much the same as through about 1991.
You may need to adjust your shift linkage after you install the column. Be sure to chalk your wheels.
The piece that goes between the end of the column and the steering box can be a biatch if you do the swap alone. It is easier to attach it to the column first, then the box if doing this by yourself. If you have a helper then you can easily get it back on without removing that part from the steering box.
So, to make a short story as long as I possibly can:
1. This is plug and play. Too easy!
2. Use the wiper delay box or your wipers will not work right if at all (plus you get delayed wipers!!).
3. You may need to adjust the shift linkage!
4. Spend the money, buy all new guts, tear it down and "rebuild" it (the $250 service online is about an hour job to tighten four bolts, clean and lube everything. Takes three or four hours your first time so get three columns and do them all at once. The last one is a piece of cake).
5. You just need to flip the plugs on your ignition switch. Plugs and wires are the same otherwise.
6. You may as well swap the lock cylinder so your friends will stop hiding your truck while you are in Wal Mart!
7. A good paint job on the column will make her look good too!
Again, I think you may be able to use columns up to 1991, even from the newer style C/K series trucks but I am not for sure. I know an 88 will work and the columns I looked at in the junk yard a few weeks back look the same but I did not look at the back up switch, ignition switch, dimmer switch, or signal harness. If different, those items can most likely be changed out.
Good luck. and have fun! Take a cordless impact with you with extensions! Makes taking a column out much easier!