Thank you all for your replies. If it were longer, I would go the
engineered
wood route, but its only a couple of 2 x 6's.

I did not think of the plywood being a stabalizing factor, but of course it
is.

And I did not think of gluing it all togeather.

Glue, plywood and long nails, clinched over. I feel much better about this
now.