Drilling Steering Column?

[Zilverado]

So now that I replaced my cheapy tach with a slightly more expensive cheapy tach (that actually works at below 1000rpm), I'd like to mount it a little more permanently on the tilt steering column. I am currently using a hose clamp, but that's just not cool.

So, can anyone tell me what is inside the steering column - the part that rotates as the shift lever is moved? I plan to mount it so that the tach is just below the left signal indicator when in drive. Is there room inside this "collar" for the tips of small screws to stick through. Not to mention what I might hit when I drill it.

I'll post some pics of the finished product when complete.

Any thoughts on that?
Thanks