I know the factory fan/clutch as well as Hayden replacement thermal/viscous clutches can take strip time. Don't know about that particular unit. If not sure, I'd suggest return it and find a JY fan and match it up with a Hayden clutch from NAPA.

I understand the late 70's 318/360 used a fan that is same/similar to the 5 blade MP used to offer. If you need more cooling, there are 7 blade fans. I have one from my '78 400 core out of a Cordoba. The 7 blade would need the heavy duty replacement clutch.

Bouchillon used to offer a 6 blade fan also.