66 fan and crank pulley identification?
Hi guys, I spent most of the day in front of the bead blaster. The fan pulley on my 66, 300 hp motor with power steering is a 2 groove part number 377024500 or CC? Does any one know what this pulley came on originaly? I have and think that my car is suppose to have a single groove pulley part number 378847200. Can any one varify that this one is correct for my car? I also have a crank pulley 2 groove part number 3744043BA GM. Is this the right pulley for my car? Any help will be appreciated. Thanks, Bruce
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Re: 66 fan and crank pulley identification?
Bruce, You are in a real gray area. I have been through the same thing on my 65. Your fan pulley is suppose to be a double groove and the number you listed 0245 is one of the combinations available. Joe Lucia is very helpful and more knowledgable then I on this. Also there is a lot of info in the archives especially from some of my posts that others answered. Good Luck! Mike -
Re: 66 fan and crank pulley identification?
Bruce-----
For your application, I would expect that a waterpump pulley of GM #3788472 would have been used. This is a single groove pulley.
For the crank pulley, I would expect that a single groove GM #3755820 pulley would have been used. For the power steering driver, an add-on pulley of GM #3751232 would have also been used.
It's also POSSIBLE that a 2 groove crank pulley of GM #3744043 could have been used in conjunction with the 3751232 power steering driver add-on pulley. In this configuration, one of the available crank primary pulley grooves would have been unused. I don't know if this configuration was used, but it MAY have been.
It's also POSSIBLE that the 2 groove crank pulley of GM #3744043 was used without an add-on power steering driver pulley. In this configuration, both grooves would have been used, one for the waterpump and alternator and the other for the power steering driver.
What kind of power steering PUMP PULLEY do you have? Is it a "3 spoke" cast iron pulley or a "pancake" stamped steel pulley?
The GM #3770245 waterpump pulley that you have was used for 1966 L-79's. As far as I know, this pulley was not used for 300 hp engines, though.In Appreciation of John HinckleyComment
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Re: 66 fan and crank pulley identification?
Hi joe, I have the stamped pancake style power steering pulley. I have not checked the crank pulley on my motor yet. I thought the existing fan pulley, 2 groove( 3770245 ) was wrong. So I picked up the single groove ( 3788472 ) to replace it with. The ( 3744043 ) crank pully came with it. they were sold as a set at a swap meet. I will be pulling my motor from the car this winter and will check the existing crank pulley at that time. Seems there were many posibilities with respect to whats correct for my car. I just don't understand why GM would install a 2 groove fan pulley and only use one groove to run the fan and alt. The power steering pump is run off the crank pulley only. My car never had AC. Thanks, BruceComment
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Re: 66 fan and crank pulley identification?
Bruce-----
I think you will find that using the existing "pancake" style power steering pump pulley (likely GM #3770509), the power steering pump pulley will not align with either of the two grooves on the 3744043. In all cases I know of, to use the 3770509 power steering pump pulley, which IS the correct power steering pump pulley for your application, you must use the GM #3751232 add-on crank pulley. In that case, that will still leave one of your 3744043 grooves unused. Using the 3755820 pulley in conjunction with the 3751232 add-on pulley results in no unused grooves. I think that either the 3744043 or 3755820 crank pullies can be used, but if the 3744043 is used, you end up with the unused groove.
Of the combinations possible, I believe the 3755820 crank pulley in conjunction with the 3751232 add-on pulley with the 3788472 waterpump pulley is what was used originally for your application.In Appreciation of John HinckleyComment
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