Heatsoak is sure an issue. Especially to the turbo people, but unfortunately not my problem.

I'm no expert, but I've been messing with this theory for a while. Biggest problem I figure is the fact that the good ol ford has a metal inlet manifold bolted (almost) directly to the rather hot head. You'll find a lot of "modern" cars have a plastic manifold, which looks cheap and nasty, but the inlet temps are a lot less. The falcon BBM manifold hits about 70 degrees C on a normal QLD day, and the metal temp moves upwards to 85 plus in traffic. I can't see why it wouldn't reach the water temp (93 degrees??? ) if idled long enough.

I've used an aquarium digital temp unit to measure intake air temps in the inlet on my AU, and with a 25 degree day, the air is already 40 degrees odd at the throttle body ( BA inlet, heat wrapped, XR snorkel ) and this is with the throttle body metal temp at about 50 degrees. This is average operating temp, average surburban speeds. I haven't been game to drill a hole in the alloy manifold for testing yet, but I assume the air will be 10 degrees odd cooler than the metal by the time it hits the head, so it gets up towards 80 degrees!!!

In comparison my wifes PT cruiser with a plastic inlet manifold is only at 30 degrees at the throttle body ( plastic airbox, cold air pipe ) and the plastic temp next to the head is only about 50 degrees!!!!

So the ford BBM/alloy inlet is a air oven.

I've tried a air blower sourced from a boating shop that blows a huge amount of air on 12V and all it does is delay the BBM manifold hitting it's peak. I think it would make sense to duct air up into the engine compartment to keep the whole area as cool as possible, and bonnet vents seem a great idea to me. Air blowers from boat shops cost from $25 to $80 depending on how flash you want. I'm messing around with a temp switch to activate it, but it would have to be linked to a air pressure switch so it only activates when you are stationary, and not on the highway on a hot day.

Sorry to rave on, but I think the next big key will be a phenolic inlet manifold gasket, as described on Autospeed about 2002. The idea is a phenolic plastic inlet gasket of about 6mm that insulates the inlet from the head. This high temp plastic is supposed to drop the inlet air at least 10 degrees, and can only help all fords. Finding suitable phenolic and match porting it is my current delimma, but will have a working model before Christmas. Phenolic insulators are commonly advertised for four barrel carbs on v8's for keeping the carb cool and not vapour locking. Phenolic is quite cheap, but hard to find so far....

I took the sealing rubbers off the front and rear of the engine bay where it seals against the bonnet, and removed the bonnet insulation on the underside. The average air temps did drop a fair bit, more air getting in, less heat trapped. I'd like to remove the rear lip altogether, as this would duct all the trapped hot air up over the windscreen. Probably sucking that in through your vents though.......

you would end up with a quickly fogged up window in the rain

sorry, just re-read some previous posts and realise I've raved on about off topic stuff. You'll be old one day too....

The factory heat shield doesn't go back on cause it is difficult to fit on most extractors from what I've heard.