Radiator Choice

[tahart]

The primary difference is the fan bolt circle. 2710 and 2711 both have a 3.00 fan bolt circle, have the same pilot diameter and depth, but 2711 is just a bit shorter. 2765 has a 3.25 fan bolt circle, a larger pilot diameter and shorter depth. Hayden does have an adapter to reduce the pilot diameter on the 2765 down to the same as the 2710/2711.

What I have seen is that there are several different 7 blade fans for the 428, and they all look the same. I have a huge 19.5" fan and it is the 3.00 fan bolt circle, so a 2710/2711 should work. I have seen fans that are 18.5" that have the 3.25 fan bolt circle. You couldn't use a 2710/2711 with that fan, and would have to use a 2765. Hayden makes several universal type fan clutches with a 3/25 fan bolt circle also. 

[tahart]

What diameter is the C9ZE fan?

[69 GT350 Vert]

C9ZE-E is 18.25 inch diameter according to mustangtek.

https://www.mustangtek.com/fanclutch.html