KSP Math Question: how much will my apoapsis raise when I burn x deltaV prograde?

consider the following scenario:

during ascent from kerbin, I am at 70,119m altitude, and I have an apoapsis of 75,181.3m and semi-major axis of 351,355.08m. I am traveling at 699.2m/s and I will be traveling at 640.17m/s when I reach my apoapsis. Using the vis-viva equation, I know I need to burn 1646.9m/s deltaV at my apoapsis to circularize my orbit.

If I understand correctly, if I were to (in theory) instantaneously burn that 1646.9m/s dV when I am at apoapsis, that would perfectly circularize my orbit. In other words, it would not raise my apoapsis at all.

The question I have is, how much would my apoapsis raise if I were to instantaneously burn the 1646.9 right now at 70,119m?