I agree.
The stock radiator was no match for the improved 'heatsource' on the other end.

Had a chuckle when I noticed this pic comparing the 2 waterpumps;
http://st.hotrod.com/uploads/sites/21/20...-sheetmetal.jpg

I've tested a number of these on my own engine and found the factory stock 'childs toy' stamped impeller provided way more flow through the system then the 440source one with the cast impeller.
The cast impeller 'should be' better, but is probably not designed that well.