The Blackman posted:

Thanks Peter for your reply
The supercharger option has always scared me for that very reason. Would an intercooler and bonnet scoop solve the problrem of heat from a lack of underbonnet airflow. I dont think i would turbo the donk without an intercooler

Peter 2 posted:

The chap had the harmonic balancer come off twice! second time stuffed the engine.
The problem isn't so much that air can't get in but it can't escape after passing through the radiator, although spotties bull bars and all the other crap we fit doesn't help.
Toyota had heat probs with the 2H powered 75's in the late 80's, they went through batteries very quickly in hot climates. they installed a vent in the LHS mudguard behind the Landcruiser badge to try and remove heat.
when the 1 hz came out in 1990 they changed the rad slightly and as the motor was 'cleaner/narrower' the air got out better but they still ran hotter than in a wagon.
I suspect that getting the air out might be the harder job, lifting the trailing edge of the bonnet means hot air hits the windscreen/gets sucked in the cabin air intake when on fresh/heats up the cabin, which in turn adds to A/C load etc. Lifting the trailing edge of the bonnet also eventually cracks the bonnet due to it being unsupported.
Fitting vents to the bonnet creates the same problem with hot air hitting the screen/cabin air intake.
Keeping the front of the truck free of airflow obstructions, the cooling system in tip top condition, keep the load down so it isn't working too hard, keep to normal size tyres to avoid increases in load bought about by larger rolling dia's in other words keep to the kiss principle.