Fan Issue Blue Print 360
Are you using the cast iron water pump and 67 273 pulleys?
Sounds like not.
'70 up cars came with engines, timing cover, water pump, that match the '70 up radiator support radiator and fan shroud.
When using a later water pump and associated components in the earlier cars some modification is neccessary.
The '70 radiators are taller (IIRC in the core) and sit further back on their mounts. I've resoldered them to allow more room for-aft and to sit low as will fit, but thats not an option with aluminum.
The earlier fans were available in 3, maybe 4 diameters. They have a small notch to clear the bubble top pre-70 radiator top tank.
Before getting anotehr replacement fan, look at the FSM to get a handle on the diameter and blade sizes used for various applications. Also the spacers used in 70 up vs 67-69 down. Theres also at few threads here comparing such things along with various fan clutch dimensions.
