Don't do that. It is going to wobble everywhere.
At best, you could drill in holes at the edge of either side, then do that top & bottom. But I would still not want to do it like that.

Get a pole strap with a bracket. That will give you a flat surface to mount to.
Something like this: [Link: penningerradio.com]
Get 2 of those, one for the top part of the mount and one for the bottom. That should easily hold up to a 55". Bigger than that and you might have to search for awhile to find something more heavy duty.