'77 Fan upgrade to 11 blades: Which fans work?

[tdw28210]

Hi,

Been trying to figure this out. I am looking to replace the 5-blade on my '77 S with an 11-blade. There seems to be a few various part numbers that may/may not work. Can anyone share a definitive part number they KNOW works? Like through actually installing it and seeing it work?

And I assume the housing does not need to change, but if I am wrong about that, please let me know. Thanks in advance as always.

[Bill Verburg]

Originally Posted by tdw28210

Hi,

Been trying to figure this out. I am looking to replace the 5-blade on my '77 S with an 11-blade. There seems to be a few various part numbers that may/may not work. Can anyone share a definitive part number they KNOW works? Like through actually installing it and seeing it work?

And I assume the housing does not need to change, but if I am wrong about that, please let me know. Thanks in advance as always.

you have a 5 blade 245mm fan
you want an 11 blade 245mm fan
best is the '85-89 3.2 fan, it has additional slots to cool the alternator, use w/

next best is the '80-84 SC

last choice is the '66-74 fan

use w/ the stock pulley halves for best effect, 1.8 ratio

[Targalid]

As Bill said, use the original pulley set up to get the most cooling from your new eleven blade fan. The 1.8 ratio with the eleven blade fan gives the highest airflow of any pulley set up. You will love the sound. Compared to the five blade fan it sounds like a low flying jet aircraft.

[tdw28210]

Thanks Bill. Thanks Targalid.

[chrismorse]

If the 74 is the last option, does that mean that an "upgrade" from a 74 to an 85 11 blade fan would improve the airflow on the 74???

Is it enough to be worth doing???

chris

[Flat6pac]

80 through Carrera with the small holes in the pulley halves. With the 77 crank pulley you'll need the 9.5 x 725 belt.
Bruce