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Are harmonic balancers for 1970 LS-5 big block rebuildable or restorable? Is this part still available from GM under its original number/configuration?
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Tony -
Re: C3 Harmonic Balancer
Tony-----
There may be a few firms out there that do this sort of thing. Primarily, I think it's for "irreplaceable" sort of balancers. I'm not a big fan of "field" harmonic balancer rebuilding.
In any event, the balancer for your application is still available from GM, although not under its original part number of GM #3963529. The current GM part number is GM #10216339. Unfortunately, although this part will SERVICE your application perfectly, its configuration is not the same as the original. Primarily, the difference is OD. This balancer has an OD of 8" and I believe that the 3963529 balancer is 6" or, possibly, 7" OD.
Another option for you is aftermarket. Aftermarket balancers are usually configured identical to stock, plus they're less expensive than GM. Try your local NAPA store.In Appreciation of John Hinckley -
Re: C3 Harmonic Balancer
Tony-----
I think that a Balkamp brand balancer part number BK 6005209 available at NAPA might be what you need. I've not seen this particular unit, so I can't say, for sure. However, most of the aftermarket replacement balancers that I have seen have been absolutely identical to stock GM. I expect that whichever company makes these for GM also makes them for many others. Check with a NAPA store to see if this unit is, indeed, the same diameter as your original. If it is and if you need a balancer, I'd give it a try. It's only about 65 bucks, too.In Appreciation of John HinckleyComment
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Re: C3 Harmonic Balancer
Thanks Joe.
I plan to pick one up at NAPA tonight and compare it to the original.TonyComment
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Re: C3 Harmonic Balancer
Tony-----
Let me know how it turns out. I'm interested.In Appreciation of John HinckleyComment
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Re: C3 Harmonic Balancer
Joe - if the service replacment balancer is 8" versus 6-7" on the original, how would this work without changing the timing cover on the engine so the tab is welded in the correct position? Is this vintage of cover the style with the bolt on pointer versus weld on and will the replacment require a different pointer as part of the change?..thx, CraigComment
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Re: C3 Harmonic Balancer
Craig-----
I was wondering the same thing, myself. I thought that the original LS-5 and LS-4 balancers were between 6 and 7" OD. The part which I mentioned which GM catalogues as a replacement is 8" OD. As I've checked further into this, though, I'm no longer convinced that the 70-74 454 balancer was between 6 and 7", like earlier L-36 427s. It may well have been 8".
As far as I know, all 1970-74 big blocks used timing tabs which were welded to the cover. However, they may have switched to the bolted-on tab about 1973. For the bolted-on tab, only one tab was ever available for these covers.In Appreciation of John HinckleyComment
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Re: C3 Harmonic Balancer- Thx Joe! *NM*
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Re: C3 Harmonic Balancer
Craig and Joe,
The 70-72 TIM&JG states the harmonic balancer is 8" diameter x 1¾" wide. So I think the timing tab concern becomes a non-issue that was a concern of mine, too.
I ordered the balancer from NAPA. It will be in on Monday or Tuesday next week. The catalog at NAPA stated 8"D x 2"W and 16 lbs. I'm not sure how that width will work out as far as alignment of belts but I will report back on my findings when I get the part. It also mentions the part being solid (1-piece). Weren't originals 2-piece with gasket?
Regardless, I will contribute the details when I get the part.TonyComment
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