Harmonic Balancer for 72 LT-1

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Dec 21, 2010 | 11:29 AM

vince6501

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From: Austin TX

Harmonic Balancer for 72 LT-1

I am buying a new harmonic balancer for my 72 LT-1. I am restoring the car back to original status. I do not have the original HB. I am buying one from Summit Racing since GM is no longer making that part. I just want to make sure that I have the proper size. I am seeing sizes that range from 6 to 8 in on this forum. Does anyone know the correct dimensions for the 72 LT-1 350 engine?

Dec 21, 2010 | 11:38 AM

69autoXr

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From: Detroit MI

I believe the LT-1 balancer is 8" x 1-11/16". Look up PN 8571N at Year One. I plan to get my next one from there.

http://www.yearone.com/serverfiles/f...ain2.asp?cat=8

Last edited by 69autoXr; Dec 21, 2010 at 11:40 AM.

Dec 21, 2010 | 12:39 PM

wcsinx

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Pretty much any of these will work...

http://www.summitracing.com/search/D...Ns=Price%7cAsc

I got this one...

http://www.summitracing.com/parts/SUM-161358/

Seems to be a quality piece and it has 60° worth of timing marks ground into the face so I don't have to screw with tape.

Dec 21, 2010 | 02:38 PM

73, Dark Blue 454

Melting Slicks

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From: Austin TX

Are you purchasing this as part of an engine rebuild? Or are you swapping HB's on an existing engine?

If it's only a HB swap, have the new HB balance matched against the old one.

Dec 21, 2010 | 03:11 PM

larrywalk

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From: St Louis MO

The original balancer was neutral balanced, so no need to do anything special.

Dec 21, 2010 | 05:35 PM

Alan 71

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From: Westminster Maryland

Hi Vince,
72, LT-!, NICE!!
Since you're "restoring the car back to original status" have you considered trying to find a good used balancer?
Just a thught!
Regards,
Alan

Dec 21, 2010 | 06:44 PM

Two Red Vettes

Burning Brakes

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SPAM alert!

I have the exact factory balancer you need. I bought it from Dr. Rebuild, painted it up Chevy orange, but never installed it (still in the box).

PM if interested.

Thanks

Dec 22, 2010 | 03:06 PM

vince6501

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Cruising

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From: Austin TX

I am trying to stay as close to original equipment as possible. Does this one match pretty close to oe?

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Dec 22, 2010 | 03:07 PM

vince6501

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From: Austin TX

That is the problem. I do not have the original HB.

Dec 22, 2010 | 03:17 PM

#10

vince6501

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From: Austin TX

Quote:

Originally Posted by Alan 71

Hi Vince,
72, LT-!, NICE!!
Since you're "restoring the car back to original status" have you considered trying to find a good used balancer?
Just a thught!
Regards,
Alan

I have looked on Ebay but did not see any. Hard to find one when I don't know exactly what I'm looking for. Any thoughts on where to look?

Dec 22, 2010 | 03:46 PM

#11

larrywalk

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Joined: Oct 2002

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From: St Louis MO

http://www.summitracing.com/parts/NAL-88960604/

Dec 22, 2010 | 03:59 PM

#12

vince6501

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From: Austin TX

Quote:

Originally Posted by 69autoXr

I believe the LT-1 balancer is 8" x 1-11/16". Look up PN 8571N at Year One. I plan to get my next one from there.

http://www.yearone.com/serverfiles/f...ain2.asp?cat=8

I checked with Y1 and they can no longer get that one. GM is not making them anymore and that one is an OE part.

Dec 22, 2010 | 04:15 PM

#13

Alan 71

Team Owner

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From: Westminster Maryland

Hi Vince,
I didn't mean to imply that it would be easy to find, I was just wondering how original you were trying to be.
I'd try Paragon Vintage in Michigan, and Gale Gee Auto in Pennsylvania.
Regards,
Alan

Dec 22, 2010 | 04:52 PM

#14

69autoXr

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From: Detroit MI

Quote:

Originally Posted by larrywalk

http://www.summitracing.com/parts/NAL-88960604/

Interestingly the GM Performance Parts catalog lists this as an externally balanced damper, yet Summit says internal. Not sure who's right.

Dec 22, 2010 | 05:47 PM

#15

73bbc

Pro

Joined: Nov 2004

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From: Atlanta area

Vince,
If you're interested in a NOS original 8" balancer, I might still have the one that I bought in the 70's but never used. If I still have it I would consider swapping it for a Fluidamper if you're interested.

Dec 22, 2010 | 05:57 PM

#16

larrywalk

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From: St Louis MO

Quote:

Originally Posted by 69autoXr

Interestingly the GM Performance Parts catalog lists this as an externally balanced damper, yet Summit says internal. Not sure who's right.

I saw that too, but when I checked the applications, it has to be the neutral balancer - I'm quite sure it's neutrally balanced.

Dec 22, 2010 | 06:26 PM

#17

Solid LT1

Le Mans Master

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From: Fremont CA

Quote:

Originally Posted by 73bbc

This is the best offer out there, I have a used one and I would want $200 for it. If this guy really has the right thick LT-1 dampner and will trade for a "street fluid dampner" I would do it!

The ones Summit sells are too thin compared to the original LT-1 balancer.

Dec 22, 2010 | 07:55 PM

#18

69autoXr

Melting Slicks

Joined: Jan 2004

Posts: 3,247

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From: Detroit MI

Quote:

Originally Posted by larrywalk

I saw that too, but when I checked the applications, it has to be the neutral balancer - I'm quite sure it's neutrally balanced.

An older GMPP catalog doesn't list it as external. Also Jegs lists it as internal as well as Summit. It's also described as 1-11/16", which should be the correct thickness for LT-1.

Dec 22, 2010 | 09:20 PM

#19

vince6501

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From: Austin TX

Quote:

Originally Posted by larrywalk

http://www.summitracing.com/parts/NAL-88960604/

Thanks for the link. I ordered this one. I hope you are right. I had ordered another one from Summit (that was made by Dorman) but it was 6 3/4" and from what I hear on this forum, it is the 8" one that came on the 72 LT-1. Guess I will send the smaller one back.