Thermos or clutch fan?

[65 Fastback]

Hi there,

I'm installing the GM serpentine pulley kit on a rebuilt 400 SBC going into my 72 C10
http://www.gmpartsdirect.com/results...umber=12497698

Can any one advise whether i'm better off installing a thermo fan or installing a new suitable fan and clutch assembly.

The kit comes with a reverse rotation long pump where as the motor in the truck now is set up with a standard short pump with the large stock shroud with a fan.

I guess the long pump with a fan is going to be an inch or 2 closer to the radiator.

If I go for a thermo bolted to the radiator do I need a different shroud?

Engine is producing 520HP at the flywheel

Thanks for your help...

[65 Fastback]

This is my current set-up

[firedemon]

Im not sure but if the pump is going reverse wouldn't the fan be going the wrong way ? might need electric

[GASoline71]

It's a serpentine setup... so the pump is supposed to turn backwards.

That shroud doesn't look stock...

Gary

[firedemon]

I understand the pump is supposed to turn backwards but the fan blades are angled to pull air with the fan turning the other way unless its a backwards fan too ?

[franken]

Link didn't work.
May I ask why the serpentine swap? Seems expensive for what benefit? High RPM throws belts?

[65 Fastback]

Sold old motor currently in truck with all accessories.

[kwmech]

I did the same thing in my 69. Full serpentine set-up with a reverse fan and fan clutch out of a 90 suburban. I also went with the big block fan shroud. I took it one step further since I had the parts, I installed the big block engine stands and mounts and moved the engine back the 1-1/4''........... dimensions came out perfect for the set-up. AND for the record, I have never had an electric fan set-up work for me correctly and keep the engine cool like a good old fan blade.