If allergic to penicillin can I take amox/k clav 875-125?

Absolutely not. Amoxicillin is simply a modified penicillin in which they added an amino side chain that can ionize and therefore add some gram negative coverage to the drug.

Its the same but stronger.

If you are allergic to penicillin you may also be allergic to amoxicillin and clavulanate, I suggest you consult with your Dr., for your own safety of course.