The mounting plate changed under the dash I found that out when I went to put a 79 tilt column in my 77 CrewCab 78 tilt column is a one year only column look it up in the factory parts book like I have

The hole where it passes through the firewall is the same I have a dozen or so columns I can take the pics of to show what I'm talking about

I restore & sell the tilt columns for 78-80 trucks I know what fits & what don't