3 core huh? What brand? That has to be a crazy fit -- how did you do it? I would love to see a photo...

I mean look how tight this is with a dual core and LS3, still more work to do on the hoses to keep them away from the rotating assembly -- a bigger radiator just would not likely fit right:

 

was tight fit but the first thing i bought ,i have automatic .too ,an the price was unbeatable to ,was only half inch wider ,but direct fit ,i dont have all the ram air in the way either that hose for your water pump too an thatb electric water pump stick out more ,probley a picture at my garage ,but .hear champion ,an i think it was the best deal i got at 216.00 shipped on ebay works great .iwas told 2 or 3 dore was only 1/4th inch different ,4 core was way out there on price,the fan.s are very close ,but good for cooling it off fast,no crazy fit ,our builds are different.3rd pic shows how close to shruad its close as you can see but works great