Just wondering how well the above rad would cool a 8800gts and a overclocked core2duo?
With which fans? Core2Duo overclocked to what speed with what voltage? With what pump?
Without answers to the above, no-one can give any form of valid advice... heatload isn't quantifiable due to lack of info regarding level of overclock. Airflow required to remove heatload isn't quantifiable as you haven't mentioned what fans you intend to use. Flowrate isn't quantifiable as you haven't mentioned what pump you intend to use.
Max power consumption = max heatload (approximately)
Therefore, use
http://extreme.outervision.com/psucalculator.jsp to quantify heatload (only select the items being cooled and the pump, and knock 38 off the total). Once that's done, reference the chart below to ascertain which fans will provide the answer that you want... and which ones won't. Assume flowrate to be between 5 and 6lpm assuming you choose the "correct" pump (D5 or DDC Ultra).
Pf H = Panaflo FBA12G12-H1A - 105cfm, 6.8mmH2O, 41.5dBA @ 12v
1212M = Delta WFB1212M - 72.4cfm, 3.4mmH2O, 34dBA @ 12v
Nexus = Nexus D12SL-12 - 36.8cfm, 22.8dBA @ 12v