Weird ? about small block pulleys
This is what I'm gathering....
To increase the cooling capability of the system...
If you need more airflow through the radiator you do the following.
1. Speedup the shaft speed
2. Increase the number of fan blades
3. Increase the diameter of the fan
4. Increase the blade pitch
If you increase the shaft speed you do the following to the water pump.
1. Increase flow
2. Increase pressure
3. Increase the chance of cavitation
To reduce chance of issues from the above...
1. Decrease the OD of the impeller
2. Decrease the number of vanes
This video also does a good job of explaining (much better then me!)
And for a little light reading
https://www.sciencedirect.com/science/article/pii/S1110016819300109
Here is the same chart from the 67 FSM
This is what I'm gathering....
To increase the cooling capability of the system...
If you need more airflow through the radiator you do the following.
1. Speedup the shaft speed
2. Increase the number of fan blades
3. Increase the diameter of the fan
4. Increase the blade pitch
If you increase the shaft speed you do the following to the water pump.
1. Increase flow
2. Increase pressure
3. Increase the chance of cavitation
To reduce chance of issues from the above...
1. Decrease the OD of the impeller
2. Decrease the number of vanes
This video also does a good job of explaining (much better then me!)
And for a little light reading
https://www.sciencedirect.com/science/article/pii/S1110016819300109