shmolton, at first glance...
i say no.
I would have to understand the loading on the 2nd floor, but as a starting point, i would start at 3 2x8's sandwiched together..
But don't take my word for it, since i did not do an analysis of the exact condition. If it is load bearing wall that you are replacing, two 2x4's does not sound big enough.
CT
Is this a good Stock?
Anything I say in the post above is my OPINION only. (Ne buvez pas l'kool-aide.)...and don't be a MARKEY.