In a conventional engine design, coolant first enters the block and then the head. The result is that the coolant is already quite hot by the time it reaches the head.
In 1992, Chevrolet introduced the C4 Corvette along with its then revolutionary V8 engine that featured a “reverse cooling” system. This routed coolant first to the heads which then flowed down through the block. This kept the heads cooler, and permitted higher compression and consequently more power.
Reverse cooling also improves radiator performance. Since the coolant first enters the bottom of the radiator, not the top, the flow of coolant helps flush air bubbles out of the radiator passages, improving its efficiency.
All this from a simple reversal of standard direction. Principle 13 – The Other Way Round