Pulleys for 1966 L79 with power steering

[Steven L.]

I'm trying to piece together the correct pulleys' espeically the crankshaft pulley(s), for my '66 L79 with power steering. I've looked at several different reference resources, including the assembly manual, but there isn't much info under the L79 option. Under N40, the assembly manual illustration shows the 3890419 water pump pulley, and what looks like a crank pulley with the 3751232 pulley added in front of it. The only reference to a L79 crank pulley that I have found is 3858533, which I have one of, but the 3751232, which I also have one of, will not fit on top of it. Is the 3858533 pulley the only crank pulley needed?

Thanks,
Steve Leunig
#62965

[Joe L.]

Re: Pulleys for 1966 L79 with power steering

I'm trying to piece together the correct pulleys' espeically the crankshaft pulley(s), for my '66 L79 with power steering. I've looked at several different reference resources, including the assembly manual, but there isn't much info under the L79 option. Under N40, the assembly manual illustration shows the 3890419 water pump pulley, and what looks like a crank pulley with the 3751232 pulley added in front of it. The only reference to a L79 crank pulley that I have found is 3858533, which I have one of, but the 3751232, which I also have one of, will not fit on top of it. Is the 3858533 pulley the only crank pulley needed?

Thanks,
Steve Leunig
#62965

Steve------

waterpump pulley-------GM #3770245

crankshaft pulley--------GM #3858533

p/s pump pulley---------GM #3834720

alternator pulley---------GM #3875968

no crankshaft ad-on pulley is used.

[Brian K.]

Re: Pulleys for 1966 L79 with power steering

Joe, my info has the alternator pulley for a N40 only option 66 L79 as pulley 3829387 also the upper alternator bracket is different and part number 3868882 is used.

[Steven L.]

Re: Pulleys for 1966 L79 with power steering

Thanks Joe! Wow, any idea why there is so much conflicting info on what the pieces of the power steering setup are? I ask because the assembly manual info doesn't jive with the info in the Chevy parts books I have, including a 1967 book, and there isn't anything mentioned in several of the Corvette books I have.

[Steven L.]

Re: Pulleys for 1966 L79 with power steering

Thanks Brian. Is your info on the use of the 387 alt pulley documented someplace? Also, can you verify the alt bracket number, as there are only six digits in the number you provided.

[Joe R.]

Re: Pulleys for 1966 L79 with power steering

I'm trying to piece together the correct pulleys' espeically the crankshaft pulley(s), for my '66 L79 with power steering. I've looked at several different reference resources, including the assembly manual, but there isn't much info under the L79 option. Under N40, the assembly manual illustration shows the 3890419 water pump pulley, and what looks like a crank pulley with the 3751232 pulley added in front of it. The only reference to a L79 crank pulley that I have found is 3858533, which I have one of, but the 3751232, which I also have one of, will not fit on top of it. Is the 3858533 pulley the only crank pulley needed?

Thanks,
Steve Leunig
#62965

Hi Steve:

The only time that GM used the 3890419 and 3751232 pulleys on the L79 was when the L79 had *both* power steering and A/C. If you have only power steering and no A/C, the pulleys that Joe Lucia listed are correct.

[Brian K.]

Re: Pulleys for 1966 L79 with power steering

There is a very good 1966 small-block pulley article in the spring 2009 NCRS Restorer. It explains in depth with photos and part numbers the article by Mark Gorney & Jim Williams answered every question one could ask about pulley aplications on a 327 Corvette built in 1966.

[Brian K.]

Re: Pulleys for 1966 L79 with power steering

Steven do a search on the 3829387 on this board and you will see it referenced for 66 L79 use including a previous post by Joe Lucia.

[Brian K.]

Re: Pulleys for 1966 L79 with power steering

Steven sorry the upper alternator bracket number is 3868882, I missed an 8!

[Joe L.]

Re: Pulleys for 1966 L79 with power steering

Joe, my info has the alternator pulley for a N40 only option 66 L79 as pulley 3829387 also the upper alternator bracket is different and part number 3868882 is used.

Brian------


There is conflicting information on the alternator pulley. In PRODUCTION, GM says that GM #3875968 was used. SERVICE information says it was GM #3829387. These pulleys are not interchangeable and neither was supersessive to the other.

There's also conflicting information on the brace. PRODUCTION shows that the GM #3881816 or 3884640 was used. SERVICE shows the GM #3868882.

[Brian K.]

Re: Pulleys for 1966 L79 with power steering

Joe is 3875968 a deep grove pulley? My data shows it only 2 5/8 DIA where 3829387 is 3 5/8 DIA. Mark Gorney and Jim Williams research shows the 3875968 use on 300hp cars with AC or cars with AC and PS and cars with AIR and AC and PS . Also they show no use of 3875968 with L79 which uses deep grove pulleys on all other locations except PS with AC or AIR and AC and PS combo. I wonder about the alternator brace number since 3868882 is an earlier sequence number than 3881816 or 3884640 but can't offer you no proof to say for sure.

[Joe R.]

Re: Pulleys for 1966 L79 with power steering

Joe is 3875968 a deep grove pulley? My data shows it only 2 5/8 DIA where 3829387 is 3 5/8 DIA. Mark Gorney and Jim Williams research shows the 3875968 use on 300hp cars with AC or cars with AC and PS and cars with AIR and AC and PS . Also they show no use of 3875968 with L79 which uses deep grove pulleys on all other locations except PS with AC or AIR and AC and PS combo. I wonder about the alternator brace number since 3868882 is an earlier sequence number than 3881816 or 3884640 but can't offer you no proof to say for sure.

According to some notes that I assembled a few years ago, the 3829387 is a deep-groove pulley that is 3.6" in diameter. I don't have info on the 3875968, but I'm sure Joe Lucia does.

If your L79 does not have both PS and A/C, it should have a deep-groove alternator pulley. If it has both PS and A/C, it should have a standard-groove alternator pulley.

[Brian K.]

Re: Pulleys for 1966 L79 with power steering

Looking at Mark and Jim's research their listing 3846180 for PS and AC combo and I'm pretty sure it a deep grove pulley with an 3 3/64 DIA . The only times I think L79's don't have a deep grove pulley in all positions is when they have AC and PS combo or AIR, AC and PS combo then the power steering pulley 3770509 (non-deep) is used instead of 3834720 which is a deep grove pulley.

[Joe L.]

Re: Pulleys for 1966 L79 with power steering

Joe is 3875968 a deep grove pulley? My data shows it only 2 5/8 DIA where 3829387 is 3 5/8 DIA. Mark Gorney and Jim Williams research shows the 3875968 use on 300hp cars with AC or cars with AC and PS and cars with AIR and AC and PS . Also they show no use of 3875968 with L79 which uses deep grove pulleys on all other locations except PS with AC or AIR and AC and PS combo. I wonder about the alternator brace number since 3868882 is an earlier sequence number than 3881816 or 3884640 but can't offer you no proof to say for sure.

Brian-------


As far as I can determine, the GM #3875968 is a deep groove pulley. However, it's kind of unusual in that it's a stamped steel pulley with integral fan.

By the way, while the GM #3829387, original or reproduction, is very easy to find, the GM #3875968 is extremely difficult to find. The 3875968 is not to be confused with its standard groove "sibling", GM #3843342. The latter is quite easy to find.

[Brian K.]

Re: Pulleys for 1966 L79 with power steering

Joe was 3875968 used on 327/300hp cars?