another 360/408 over heating
compression tester just arrived today
I was thinking more about a cooling system pressure test since you say it never pressurizes.
my work with airflow suggests that anything flat directly behind the radiator causes a high pressure zone that blocks air flow.
As others have noted the flappers are there to close in stop and go / ideling and force air to pull through the rad but allow for free flow of air at most other conditions.
Simple thing to do is measure the diameter of every opening in the shroud and do the math to find area for each opening A=3.14 x (D/2) x (D/2) (Area = Pi x R squared) (R=D/2)
As illustration...
assume 6 holes 3" dia and 2 holes 12" dia
6 x 3" holes total = 42.4 sqin
2 x 12" holes total = 226 sqin
total area = 268.4 sqin
22" rad = 21x17 core area ( where air can flow) = 357sqin
That results in about 25% blockage of air flow at speed, idling is a different ball of wax
(This is just illustration only, your numbers will be different)
