Harmonic Balancer
Thread Starter
Instructor
Joined: Apr 2010
Posts: 185
Likes: 8
From: Gilbert Arizona
Harmonic Balancer
I got a problem with a mechanic who is rebuilding my engine, it's a L-46 350-350 1969. he told me I had the wrong Harmonic Balancer on my car yet it was #3896966? Isn't that the original GM #. Sometimes it stinks being a women in a dominant mans profession because they don't want to listen. He did not believe the car was built in December of 1969 even after I proved it. Said he has a corvette guy who knows all about corvettes and they where all built months before they actually came out.
Now I am worried that he doesn't know as much as he states, so what's a girl to do? I don't want to argue with him about all my parts. So I thought if I gave him actual GM parts list maybe that would help. What do you guy's think?
Thanks Kim
Now I am worried that he doesn't know as much as he states, so what's a girl to do? I don't want to argue with him about all my parts. So I thought if I gave him actual GM parts list maybe that would help. What do you guy's think?
Thanks Kim
Limping across the line
Joined: Oct 2002
Posts: 5,299
Likes: 109
From: Peoria Az
Here's a little info.
Found this after a quick Google search
http://www.ncrs.org/forums/archive/i...p/t-96109.html
It's a lot easier these days to find information witht the intrest net and all. Back in the day I remember you had to rely on your circle of friends.
Was that you at a machine shop in Gilbert last week??
Found this after a quick Google search
http://www.ncrs.org/forums/archive/i...p/t-96109.html
It's a lot easier these days to find information witht the intrest net and all. Back in the day I remember you had to rely on your circle of friends.
Was that you at a machine shop in Gilbert last week??
Last edited by AzMotorhead; Apr 3, 2016 at 10:53 AM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Asking for detailed info will aid you in your 'battle' to prove your point. And this statement is coming form a guy who owns his own Corvette shop. SO...do not be afraid to stand your ground when you know you are right. Because I do it with my customers when I know I am right.
I can not do it right now because I am at home and my books are at work...BUT...if this is not resolved with the information in the previous post to you liking...I can check and see what I can find and post it tomorrow....and.....sometimes when GM had plant shut downs and or strikes in the labor force....I do not know how much that effects things.
DUB
Drifting
Joined: Sep 2014
Posts: 1,430
Likes: 59
From: Long beach NY
St. Jude Donor '15-'16, '18
Not off hand, i will grab a flashlight tommorow and see if i can find stamp.
If it's stamped on outer edge like timing line i may be able to help. I'll let you know tommorow.
My car has a 34,xxx vin number i dont know how close to yours.
Good luck
If it's stamped on outer edge like timing line i may be able to help. I'll let you know tommorow.
My car has a 34,xxx vin number i dont know how close to yours.
Good luck
Race Director
Joined: May 2006
Posts: 18,734
Likes: 2,582
numbers
The original number is 3947712 it was used on the L-46, LT-1, and L-82
http://www.ncrs.org/forums/archive/i...p/t-86162.html
Your mechanic should be aware of the GM strike which caused 1969 Corvettes to have probably the longest production cycle of any C3.
http://www.ncrs.org/forums/archive/i...p/t-86162.html
Your mechanic should be aware of the GM strike which caused 1969 Corvettes to have probably the longest production cycle of any C3.
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Thread Starter
Instructor
Joined: Apr 2010
Posts: 185
Likes: 8
From: Gilbert Arizona
The original number is 3947712 it was used on the L-46, LT-1, and L-82
http://www.ncrs.org/forums/archive/i...p/t-86162.html
Your mechanic should be aware of the GM strike which caused 1969 Corvettes to have probably the longest production cycle of any C3.
http://www.ncrs.org/forums/archive/i...p/t-86162.html
Your mechanic should be aware of the GM strike which caused 1969 Corvettes to have probably the longest production cycle of any C3.
Last edited by bugzbunny; Apr 4, 2016 at 04:09 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
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From: Charlotte NC
I looked in my GM parts book. And the part number you listed ...3896966...DID NOT show up in the part book. And this GM parts books last revision was back in 1983.
I KNEW there was a STRIKE somewhere during that era...just did not know exactly when.
I may be wrong.....but for the longest time...I always thought and have been told that a 400 cid is externally balanced...so the harmonic balancer is different...but a harmonic dampener is the same for a 350 cid....except for some diameter differences.
I can take a photo of the page form the GM part book and post it.
DUB
I KNEW there was a STRIKE somewhere during that era...just did not know exactly when.
I may be wrong.....but for the longest time...I always thought and have been told that a 400 cid is externally balanced...so the harmonic balancer is different...but a harmonic dampener is the same for a 350 cid....except for some diameter differences.
I can take a photo of the page form the GM part book and post it.
DUB
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
This post reminded me of a similar concern I had when I built my 383 from a Gen I 350. We internally balanced the components, and I bought this GM balancer P/N 88960604, which was advertised as a direct replacement for Hi-Performance Small Blocks. (302, LT-1, L-82 etc) But for some reason, I ended up going with an aftermarket balancer. I do not have a clue at the moment why I switched, but as I understand it, Gen II blocks with one piece rear seals and all were externally balanced? Indeed the ZZ4, ZZ383 crate engines are externally balanced. However it appears GM considers the currently available balancers to be interchangeable between old and new? Not sure what other conclusion to reach at this point.
I have the 88960604 unit brand new in the GM box if anyone is interested.
I have the 88960604 unit brand new in the GM box if anyone is interested.
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
Found this in a search.
Looks like it may be a balancer for a 67, 68 Camaro 350.
Is your car original or a NOM?
BALANCER ASSY 67 68 Chevy Camaro 350 3896966
http://webcache.googleusercontent.co...&ct=clnk&gl=us
Looks like it may be a balancer for a 67, 68 Camaro 350.
Is your car original or a NOM?
BALANCER ASSY 67 68 Chevy Camaro 350 3896966
http://webcache.googleusercontent.co...&ct=clnk&gl=us
Racer
Joined: Nov 2007
Posts: 410
Likes: 45
From: Wisconsin Rapids wisconsin
I looked in my GM parts book. And the part number you listed ...3896966...DID NOT show up in the part book. And this GM parts books last revision was back in 1983.
I KNEW there was a STRIKE somewhere during that era...just did not know exactly when.
I may be wrong.....but for the longest time...I always thought and have been told that a 400 cid is externally balanced...so the harmonic balancer is different...but a harmonic dampener is the same for a 350 cid....except for some diameter differences.
I can take a photo of the page form the GM part book and post it.
DUB
I KNEW there was a STRIKE somewhere during that era...just did not know exactly when.
I may be wrong.....but for the longest time...I always thought and have been told that a 400 cid is externally balanced...so the harmonic balancer is different...but a harmonic dampener is the same for a 350 cid....except for some diameter differences.
I can take a photo of the page form the GM part book and post it.
DUB
Thread Starter
Instructor
Joined: Apr 2010
Posts: 185
Likes: 8
From: Gilbert Arizona
Found this in a search.
Looks like it may be a balancer for a 67, 68 Camaro 350.
Is your car original or a NOM?
BALANCER ASSY 67 68 Chevy Camaro 350 3896966
http://webcache.googleusercontent.co...&ct=clnk&gl=us
Looks like it may be a balancer for a 67, 68 Camaro 350.
Is your car original or a NOM?
BALANCER ASSY 67 68 Chevy Camaro 350 3896966
http://webcache.googleusercontent.co...&ct=clnk&gl=us
Thread Starter
Instructor
Joined: Apr 2010
Posts: 185
Likes: 8
From: Gilbert Arizona
Found this in a search.
Looks like it may be a balancer for a 67, 68 Camaro 350.
Is your car original or a NOM?
BALANCER ASSY 67 68 Chevy Camaro 350 3896966
http://webcache.googleusercontent.co...&ct=clnk&gl=us
Looks like it may be a balancer for a 67, 68 Camaro 350.
Is your car original or a NOM?
BALANCER ASSY 67 68 Chevy Camaro 350 3896966
http://webcache.googleusercontent.co...&ct=clnk&gl=us
Thread Starter
Instructor
Joined: Apr 2010
Posts: 185
Likes: 8
From: Gilbert Arizona
Thanks guy's for your time and effort. It looks like 3896966 is the correct balancer so I will stick with that. It's also the Muncie 4 speed. the engine and tranny are all original and don't want to change anything there. Appreciate all the unfo.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Unless I missed something...
DUB
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
There was a balancer back about that time that was listed in the Chevy Power Catalog. Don't recall the number, but it was listed as an 8" nodular iron and was heavier than the stock one. I've still got it on the front of a 355.
Drifting
Joined: Oct 2012
Posts: 1,524
Likes: 61
From: Medina Ohio
This post reminded me of a similar concern I had when I built my 383 from a Gen I 350. We internally balanced the components, and I bought this GM balancer P/N 88960604, which was advertised as a direct replacement for Hi-Performance Small Blocks. (302, LT-1, L-82 etc) But for some reason, I ended up going with an aftermarket balancer. I do not have a clue at the moment why I switched, but as I understand it, Gen II blocks with one piece rear seals and all were externally balanced? Indeed the ZZ4, ZZ383 crate engines are externally balanced. However it appears GM considers the currently available balancers to be interchangeable between old and new? Not sure what other conclusion to reach at this point.
I have the 88960604 unit brand new in the GM box if anyone is interested.
I have the 88960604 unit brand new in the GM box if anyone is interested.
All Gen I 2 piece RMS 350's are INTERNALLY balanced.
All 400's are EXTERNALLY balanced.
1 Piece rear main seal SBC are still considered Gen I. They ARE referred to as external balance or internal/external but, they are not the same as a 400. They are technically INTERNALLY balanced, however the counterweight / flywheel & flexplate flange that is on the outside of the main seal on a 2 piece rear main seal crank, is not there on a 1 piece RMS crank. So, that weight is located on the flywheel / flexplate. The balancer is the same / neutral as a 2 pc RMS block and not used for balancing.
Clear as mud?
Melting Slicks
Joined: Oct 2001
Posts: 2,065
Likes: 1,395
From: Halifax, Nova Scotia, Canada
This post reminded me of a similar concern I had when I built my 383 from a Gen I 350. We internally balanced the components, and I bought this GM balancer P/N 88960604, which was advertised as a direct replacement for Hi-Performance Small Blocks. (302, LT-1, L-82 etc) But for some reason, I ended up going with an aftermarket balancer. I do not have a clue at the moment why I switched, but as I understand it, Gen II blocks with one piece rear seals and all were externally balanced? Indeed the ZZ4, ZZ383 crate engines are externally balanced. However it appears GM considers the currently available balancers to be interchangeable between old and new? Not sure what other conclusion to reach at this point.
I have the 88960604 unit brand new in the GM box if anyone is interested.
I have the 88960604 unit brand new in the GM box if anyone is interested.
The balancer on mine failed and I replaced it with 88960604, which, as mentioned above, is for a ZZ4 etc, engine.
The only difference is the 88960604 has an embossment of degree marks around about 90 degrees of the perimeter of the ring. A cosmetic thing that has no bearing on the look or operation.
I know the 88960604 fits/looks and works well on mine.