I also have a 440 Big Block 460-480hp. I think my current radiator is 2 core and on hot days the guage will climb and recover and once and a while burb a bit out the storage tank. I was considering an aluminum 3 core fore extra cooling peace of mind. (if it fits ahead of the clutch fan)> you mentioned a 2 core 1 1/4. Can you support that statement with a few facts that led you in that direction? Cheers Ron D