I tried the heat exchanger setup on my big block(666hp) and it wasn't up to snuff with a stock width radiator core and the most extreme conditions. (Road racing sessions) I've since separated the oil and water cooling by going to an air oil cooler. It's made a big difference in temps but I haven't been back on the track. I think a heat exchanger could possibly work with the additional width of the autorad set up and larger fans. Big blocks make BIG heat.
I went with the heat exchanger to help get the oil up to temp faster. It worked but ultimately overworked the cooling system. If you don't plan to take the car to extremes, you don't need as much cooling.