i have called summit and jegs and told them i am going to put in a 400hp engine do you think the stock radiator and dual fans are going to be good enough because they are booth new they said yes any comments would help me decide on bigger radiator or not

 

I'd say you will be fine, considering there's nothing wrong with your cooling set-up now. I don't have the same HP you have but I'm very close and my car runs around 200 in the summer. Stock Radiator, Water Pump, 195 Stat, new hoses, new Sensors and new Gage. Runs like a champ in the Texas Heat.