I copied the installation shown in the following closed thread.
http://67-72chevytrucks.com/vboard/s...d.php?t=254617
I ran into an issue where the fan vibrated since the lower mounting flange is just sitting snugly in a slot cut in the shroud. To solve this issue, I made an aluminum attachment bracket for the lower mounting flange.
That thread says that a 30A fuse will work. I had to use a 35A fuse because 30A would blow during startup. Current spikes up to around 70A during startup, and then it drops to just below 20A once its running.
One characteristic of this fan that I don't care for is that it takes about 20 seconds for it to stop spinning. It makes a decent amount of noise while it is spinning down to a stop after shutting off the engine. To address this issue, I wired the fan relay as follows so that the fan leads are shorted together through a ballast resistor when the relay is turned off. The fan stops spinning in 10 seconds now, and it is much less noisy as it is spinning down.
30 - Common - Fan power lead
87 - N.O. - Fused 12V supply (35A)
87A - N.C. - Ballast resistor (Standard Ignition RU11) - ground
I've got the fan relay wired to a Holley Sniper which is configured to turn it on at 205° and off at 195°.
Here's a video of the fan running.
https://youtube.com/shorts/XuOMMFOMKI0?feature=shared