It depends really.. 430w is getting a little low, but if you give us more details on the amperage (specifically the +12v rail) of the PSU we'll be able to help you better.
If you're confused, give us a link to your exact PSU.
I wouldn't trust it. You would be cutting it close. the 8800's loves power. I would be on the safe said and get at least a 550W or higher. And make sure your not using a non name brand psu cause it will bottle neck your system and it could cause hardware errors and crap. If i was your and if i was spending htat much on my computer i would go out and get the Corsair HX620W or even the HX520W (i use this one) which is the top of the line psu's you should go look into that/those.
I agree with schulz269. The Corsairs are great PSUs, and have plenty of amperage, to handle all that. Another good PSU, that can handle your system, not as expensive, is the HIPER 580W.