Chances are you'll be ok doing that, but not necessarily. It depends on the speaker impedance (the higher the better), the speaker sensitivity (the higher the better), and your preferred listening volumes (the lower the better).
Each of the two monoblock amps is rated as follows:
Max output power into 8 ohms: 600 watts.
Max output power into 4 ohms: 900 watts.
AC power consumption, 600 watts into 8 ohms: 1100 watts.
AC power consumption, 900 watts into 4 ohms: Not specified, but certainly a good deal more than 1100 watts.
AC power consumption, 75 watts into 8 ohms: 725 watts.
AC power consumption, 75 watts into 4 ohms: Not specified.
So if the two amps were delivering 75 watts into 8 ohms the total power consumption would be 725 x 2 = 1450 watts. 20 amps at 120 volts corresponds to 20 x 120 = 2400 watts, so you would be ok in that situation unless other things on that line drew a lot of current. But you might have a problem if the amps are required to supply power levels approaching their max capability.
Regards,
-- Al