As Morris said , just open the rear of the hood . Did that on my ERA and even in traffic here with temps in the mid to upper 90`s now in SC , I see just under 180* cruising and 190 to 195* in traffic .
I just opened the hood and turned the hood locks like they were closed , slide a piece of rubber tubing on the latch tabs so as to not damage the hood underside paint and "closed" the hood . Since the front of the windshield is a high pressure area , hood doesn`t come up and stays down so far up to 100+.
My thermostat is a 180* unit with bleed holes top and bottom . Bypass between intake and water pump is blocked as per Robert Ponds and stock ERA radiator and shrouding with a rear mounted Spal fan .
Probably doesn`t look as nice as when the hood is completely closed , but my coolant temps are good as is
oil at 200 to 210* F.