Hi Guys,
my Ace is a 1995 model with the three panels as David describes. From what I've read on other forums the 302 running temperature is around 180 to 210F, thermostat is rated at 192/195F.
Does your car have an oil cooler? Is the radiator clear of bugs and other rubbish?
The attached photo shows the vents in the oil filter access plate and the bottom plate which is not ventilated (i.e. solid plate).
The whole construction from the grill to the radiator forms a closed duct. My oil cooler is mounted sideways-on, i.e parallel with
the main chassis member together with the oil filter. If the central plate was missing then little or no air would pass over the oil cooler.
What effect an open duct has on the radiator cooling I would not like to guess, but I note that most of the cars I've looked at the radiators are not open between the grill and the radiator.
I found the access panel on my car impossible to remove as the rivet nuts had lost their grip and the slotted round head bolts had seized. I removed the flat panels on top of the inner wing under the bonnet but was faced with the same situation with these panels, so I've drilled out and renewed the majority with replacement rivet nuts and hexagonal headed bolts.
BR /Paho