Do I have enough power for dual 8800GTS 512MB?

I have a 500W OCZ ModXStream Pro.(Right after I bought it the 700W model went on a "Shellshocker" for $10 less...)
http://www.newegg.com/Product/Prod [...] 6817341016
I think I have everything I need to go SLi I just want to know if this is good enough. I got it before I was planning to SLi, otherwise I would have gotten bigger. I really don't want to get something else though...
My specs are:

Phenom x4 9950 Black Edition
4x1Gb G-Skill DDR 2 1066 RAM
ASUS M3N-HT Deluxe/HDMI Motherboard
2 SATA HDD's
1 DVD-RW Drive

http://www.antec.outervision.com/PSUEngine

well put all tdp at 100% on it

IMO you're cutting it close with 36A 12V, SLI 8800GTS, and such a power hungry CPU. I definitely would avoid overclocking it.

Running prime 95 + 3dmark vantage at the same time, the OC'ed X4 9950 (edit: total SYSTEM) consumed nearly 640W at the AC source with an HD4870x2. Had we been using Furmark rather than 3DM, it would have been much higher. http://www.tomshardware.com/review [...] 04-13.html

Stock you may be fine, overclocked likely you'll have issues. Either way, if the PSU can't provide peek demands, you'll suffer stability issues.

Not a close enough comparison, but for 1.5+ years I've run a 3.0-3.2GHz Q6600, Dual OC'ed 8800GT, 2 HDD, 2 opticals with an Antec TP3 550W and 41A 12V.