The impossible to solve overheating problem
Also you'll need the radiator support to hood seal to keep engine heat from recirculating to the front of the radiator.
treblig
This is one of the more important parts of the cooling system that everyone ignores.
a tiny bit more air from a radiator support to hood seal probably wont solve it all..
There is WAY more then a "Tiny bit" of air that gets pulled "back" thru the radiator.
The main purpose of the hood to core support seal is not to force more air through the radiator.
It is to keep the hot engine bay air from being pulled back over the top of the core support and recirculated through the radiator over and over and over continually adding heat to the cooling system.
Do a search on my username and look at my post on my cooling problems. After all I went through the hood to core support seal was what cured I would say 90% + of the overheat.
The other major improvement was getting the proper crank and water pump pulley sizes.
You say it overheats setting still or holding a steady speed. Mine car did the same thing until I put the seal in place.
I am not saying this will fix Your problem, but it is an easy and inexpensive solution to try.
Herb