Part number for a 65 corvette pulley

[Dick G.]

What is the part number I should look for on a 65 corvette 350 H.P. crankshaft 3 Groove Pulley used with power steering only. Does anyone have one? Thanks

[Eugene B.]

Re: Part number for a 65 corvette pulley

Dick,
Don't know if the 350HP is the same as my '65, 250HP or not, but my base motor uses two pulleys to achieve the 3 groove setup.

The double pulley that goes against the harmonic balancer is P/N 3744043 and the pulley that nests in it is P/N 3751232.

Hope this info. is helpful.

Regards,
Gene

[Dick G.]

Re: Part number for a 65 corvette pulley

The 65 JG mentions on base and L75 300hp cars with PS use an additional one groove pulley inserted within the crankshaft pulley to make a total of 3 grooves. On (L79 350 hp only) use a triple groove pulley. I am still searching for this info.. I will call Goat Hill.$$??

[Dick G.]

Info. on 65 350 hp with PS crank pulley?????

Goat hill is closed today. Ebay has one but it is the single groove insert type for PS. The pulley on my engine is part number stamped 3858533 2 groove. At this time I still do not know if this 3 groove pulley I need is a 2 piece (2 groove with 1 groove insert)or a 1 piece 3 groove pulley. Does anyone know? My 65 is a first week in January 65 car. Thanks

[Joe L.]

Re: Info. on 65 350 hp with PS crank pulley?????

Dick-----

No 1965 Corvette ever used a 3 groove crankshaft pulley; not even a single one. The pulley used was a 2 groove pulley of 6-5/8" OD and of GM #3858533, exactly the one you have. It is possible, though, that some of the earlier versions of this pulley were stamped with the number "3766987". By the time that your car was built, I believe the number stamped was "3858533" for some or all of the pullies used in PRODUCTION.

For power steering L-79 applications, a single groove pulley was "sandwiched" on the front. That pulley was GM #3751232. Both pullies are still available from GM.

[Loren L.]

#23561 is as Joe describes

3858533 is stamped on the pulley, along with a "GM" and "S". The single groove does NOT have the # stamped in; mine only has an "S" stamped on the back side.

[Dick G.]

Re: #23561 is as Joe describes

Thanks to all for clearing this up. Good Day!

[Wayne M.]

'65 L79 w/N40 -- combo very confusing (IMO)

Dick, I believe your car does NOT have air conditioning. Is your P/S pump pulley a single-groove cast iron, as in the '65 Tech Manual and Judging Guide ?

Same '65 TM & JG calls for "A TRIPLE GROOVE PULLEY" (singular) for L79 with P/S, although I agree with Joe L. that such an item does not exist for small blocks. What they probably meant to say is the # 3858533 double groove with the added single-groove # 3751232, which LOOKS like a triple-groove when installed.

Now refer to '65 AIM UPC N40, sheet 6: Purports to be L79 w/N40, yet the 2-groove crank pulley #3827843 is definitely a C60 (+ air conditioning) item, according to my July '65 P&A30 catalog. But this diagram does NOT show the 3rd groove to drive the compressor. Only big blocks 66+ drove both a P/S pump and A/C compressor with only 2 crankshaft grooves. So for a '65 C60 L79 N40 car, was the single groove "232" pulley stacked onto the components of UPC N40, Sheet 6, with the A/C compressor driven by belt #3, .... or, was compressor in groove #2, with PS pump driven by belt # 3 ?

And if so, what are the pulley part #'s for L79 N40 (only) ? include P/S pulley #.

[Paul Reynolds]

Re: '65 L79 w/N40 -- combo very confusing (IMO)

The 65 L79 used the following pullies for N40(PS) only(non A/C):

Crank: 3858533 Deep groove double
P/S Pump: 3834720 Single deep groove cat iron.
Alt: 3829387 Single deep groove
Water pump: 3770245 Double deep groove

The cast iron PS pump pulley lines up with the outer groove of the 2 groove crank pulley. The belt for this combination goes around the crank and PS pulleys only (not around the water pump)
The Alt belt goes in the inner groove of the crank and water pump pulleys.

The Crank, Water pump and Alt pulleys are the same as 64/65 L76 and 65 L79 without N40 (PS).

There is no add-on crank pulley required for 65 L79 with N40

65 L79 with N40(PS) AND C60(AC) use an entirely different setup for Crank, PS, Water pump and Alt.

[Joe L.]

Re: '65 L79 w/N40 -- combo very confusing (IMO)

Paul-----

Yes, you're correct. I erred in my previous response. For 1965 L-79 applications with N-40 no "add on" crank pulley was used; just the 2 groove '533' pulley all by itself. In this configuration, the "drop down" GM #3834720 single groove cast iron power steering pump pulley is used. Applications which use the "add-on" pulley (like base and L-75) also use the "pancake" GM #3770509 stamped steel power steering pump pulley.