There is a premade jumper for that very swap you are needing for your column. Go here
www.wiringharness.com
It is M&H fabricators web site. I believe the part you are looking for is 36878. Go to their site click on search by year and vehicle, and once you select 72 chevy truck scroll down about half way and you will see what it says about the part. Should be a simple plug and play swap and the part is only about $20.