Yes, too much radiator can be a bad thing. No point in running a 4 core that will pretty much limit you to an electric pusher fan when you could have run a 3 core that would have worked great and still could have used an mechanical fan or an electric puller, of which there are a lot more options. Now you'll need your giant radiator to make up for the tiny fan you'll have to run.
I run a 26" 3 core with a Ford Contour electric fan, it cools my 400-ish hp 340 great. I daily drive it and have been out in temperatures as hot as 108*, no issues. It will idle all day long and never overheat, don't have to worry about it at all.
A 22" 3 core would cool that /6 just fine, still would have been overkill, and would be way easier to set up a fan for. Heck a 22" 2-core should be overkill, and you could have run that with a nice OE shroud and a mechanical fan. If that won't cool a /6, you have other issues that you're band-aiding with a oversize radiator.