another 360/408 over heating
Problem is they are only 9" fans because I had to stagger them around the water pump due to lack of space.
I redid the calculations based on your 9" fan size
assume 6 holes 3" dia and 2 holes 9" dia
6 x 3" holes total = 42.4 sqin
2 x 9" holes total = 169.5 sqin
total area = 169.5 sqin
22" rad = 21x17 core area (where air can flow) = 357sqin
That results in about 52.5% blockage of air flow at speed.
Assuming your additional holes are 3" you have blocked off 1/2 your radiator.
I challenge anyone to block off 1/2 their radiator and try to keep the engine cool
Loose the shroud, attach the fans to bar stock frame and see how thing go.
Back in the day I had a 63 Econoline, you know the ones with the engine between the driver's and passenger's seat. it started life with a 170 inch 6 and I swapped in a 289 V8. There is no way to put a larger radiator, but I added a 3rd row stock size rad and mounted 1 15" (IIRC) electric fan on the rad, no shroud and it cooled great.
There is a number of things that go into a radiator 1,2,3 etc tubes, the size of the tubes, the pitch of the fins between the tubes, If you have more tubes you have more surface area for the coolant to come in contact with, if you have a finer pitch to the fins you have more surface area for the air to come in contact with (TO A POINT, to fine of a pitch and you obstruct too much airflow)
bottom line... the more surface area the coolant can contact and the air can contact the more heat can be transferred to the air.
Regarding cross flow "modern" radiators... those things are huge, compared to our rads... I have a 3L V6 dodge grand caravan and it has about 30x17 rad core (510sq in). The core is about about 1.25" deep with 2 x 12" fans, the shroud has many areas where it does not cover the rad.