I'm pretty sure the original A1200 PSU was 30 watts. The 68040 uses 15Watts exactly, so maybe it was a 15 watt psu.
Check the specs for a 68030. You can calculate the voltage x megahertz (5 volts?). The card and the RAM would be no concern at all.
Put in a bigger PSU if you can afford it, the system might run a bit smoother when you add hard drives and accessories.
