Does anyone know the differences between the # 3860010, 3963529, and currant 10216339 BB balancers, both cosmetically and functionally?
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Re: Harmonic balancer differences?
Mike-----
The GM #3860010 is the special high performance, 8" balancer for INTERNALLY balanced big blocks (396, 402, 427 cid) with forged crankshaft. It was originally used on all SHP 396, 402, and 427 engines, except L-88/ZL-1, from 1968 to 1971. It has no counterweighting on the reverse of the hub section. It is still available from GM.
The GM #3963529 is the high performance, 8" balancer for EXTERNALLY balanced big blocks (454 and 502 cid). It was originally used on 70-72 Corvettes with LS-5 as well as high performance 454s used in other Chevrolet chassis. It is discontinued and replaced by GM #10216339.
The GM #10216339 balancer is the current SERVICE HP and SHP balancer for EXTERNALLY balanced big blocks which replaced BOTH the above-referenced 3963529 AND the GM #3963530 SHP 8" balancer used on 1971 LS-6 Corvette engines as well as other SHP 454 and 502 engines. It is also used on most of the crate 454s and 502s.
All of the above-referenced balancers have a virtually identical configuration and appearance with the following notes and exceptions:
The GM #3860010 balancer must only be used for INTERNALLY balanced applications; it cannot be used for EXTERNALLY balanced 454 or 502 applications. It is supplied bare and unpainted;
The GM #3963529 is for EXTERNALLY balanced engines. It has a counterweighted section of the inner hub casting and is easily identified by this feature. It is also visually identical with the 3963530 but differs with respect to the state of balance (the 3963530 is "tuned" for higher RPM operation). It is supplied bare and unpainted, but is no longer available from GM;
The GM #10216339 is balanced for use in all high performance and special high performance EXTERNALLY balanced big block applications. It slightly compromises either application, but is the only SERVICE balancer available from GM for such applications. It's configuration and appearance is virtually the same as the GM #3963529 and GM #3963530, except that the outer ring and part of the inner hub are supplied painted low gloss black.In Appreciation of John Hinckley -
Re: Harmonic balancer differences?
the 339 is for external balanced 454 and 502. i cannot find a 3963529 but there is a 5963530 for LS-7/LS-7 454Comment
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correction
should be LS-6/LS-7 454Comment
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Re: Harmonic balancer differences?
Thank you, Joe and Clem. That clears up my confusion. I knew the application's but did not know how the currant 10216339 compared. Thanks again,
MikeComment
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Re: Harmonic balancer differences?
Joe the L88/ZL1 internally balanced 3879623 balancer is also still available versus the 3860010 version you describe. GM says to use this balancer with crankshaft P/N 3967811 which I believe is my 7115 forging I am using in my 66 425 engine with dimple 7/16" bolt rods. Out of curiousity, what is the difference between these units...they appear the same and will interchange. It there a difference in the rpm limits, rubber density affecting the harmonic contol, etc? I am just wondering which is best for my engine buildup...thx, CraigComment
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Re: Harmonic balancer differences?
Craig----
The '623' balancer is "tuned" (balanced) slightly differently. Use it with your crankshaft.In Appreciation of John HinckleyComment
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Re: Harmonic balancer differences?
Thx Joe, that was my thinking too.Comment
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Re: Harmonic balancer differences?
the tuning refers to the RPM(frequency)that the damper is most effective. that is why the SHP used a different one than the hydraulic lifter engines. the SHP(higher RPM) have a large mass than the regular engines. if you use a lighter weight damper to get the engine to rev quicker you take a chance of having the crank fail(crack). page 37 of the 7th edition of the chevrolet power manual explains how and why.Comment
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Re: Harmonic balancer differences?
Thx Clem - I will go look it up in the power manual...CraigComment
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