The brackets work differently for short and long water pumps. Typically the short water pump was used on 68' and back engines, with those there were no mounting hole in the heads. The long water pump started in 69' and seems to to the standard on Gen1 SBC.
You mentioned reverse flow water pump, those are almost always used with a serpentine belt drive. With this system you need to use idlers' and sometimes a tensioner to get everything turning in the right direction.
The electric fan is going to use less space, a mechanical fan often requires a fan shroud as well.
Last edited by TUTS 59; 03/02/2022 1:52 PM.