I forgot to mention that without a duct forcing air into the partitioned area the heatsoak reduced at 60km/h and above, even in traffic.
predator666: I dont have a duct rigged up to it at the moment. I will do some plenum temps very soon (end of this week/early next week)
Sil8ty: I got the heatshield from Century Foam and Rubber. It's about 8mm thick, sort of like neoprene and has a reflective foil on one side. My partition cost 2 hours of time and 4 dollars.
kjb_r33: I've been informed that the clutch fan on the engine from the factory is excellent in its efficiency and i think that at high engine speeds it pulls alot more fresh air int the engine bay thus making it cooler.
sewid: boxhead has a similar partition (made from metal) and it gets red hot. Metal partitions in my opinion suffer from heat soak and would lengthen the times to get the intake temps down.
I've posted a pic of my setup below. I know its rough, but it seals to the bonnet and the top of the wheel arch and right up to the back of the headlight and it works really well.