Have you done a temperature check to see how much difference there is between the two?

I suspect the water is moving quickly enough round the system for there not to be too great a change, though I would expect the front to run cooler simply because it is in the airflow, where the rear head hardly receives any.
_________________
MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball