Re: Internal vs. External Balance

From: Gary Hedlin (
Date: Sun Feb 28 2010 - 11:15:16 EST

If your kit was balanced, then you don't need to balance it
externally. Usually the kits have each piston and rod numbered and
the builder puts them in the corresponding cylinders.

I should say this... When I was selecting my components for my 340, I
knew it was balanced externally FROM THE FACTORY. But since I was
having it rebuilt with new pistons and rods, I spent a little more to
have everything balanced to save the hassle of having it balanced

Usually when they externally balance an engine they use counterweights
on the torque converter or harmonic balancer. But if you're going
from a external balance engine to an internal balance engine, you'll
need new ones that are neutral balance.

But I think since the 360 was internally balanced, you shouldn't have
anything to worry about.


On Sun, Feb 28, 2010 at 2:36 AM, Jamie Calder <> wrote:
> The 408 "kit" was sold to me as a balanced kit.  Does that mean it should
> have been internally balanced?
> Still curious how this is done exactly.  I know the spec sheet of the
> pistons state the weight of each one (all 524 - 526 grams).
> Are 360's externally balanced with the balancer or converter?
> If a 360 needs a new harmonic balancer or torque converter, how do they
> determine where counter weight are placed and where do they go?
> Thanks again,
> James
> --------------------------------------------------
> From: "Gary Hedlin" <>
> Sent: Saturday, February 27, 2010 11:28 PM
> To: <>
> Subject: Re: DML: Internal vs. External Balance
>> Usually an engine that's been worked on has had the internals balanced
>> (rods,pistons, crank) prior to assembly.  An external balanced engine uses
>> counterweights on the converter or harmonic balancer.  Most of  the time...
>> Unless the engine builder is a complete idiot (experience  from a 340
>> project Im working on).
>> Gary Hedlin
>> Sent from my iPhone
>> On Feb 27, 2010, at 8:41 PM, "Jamie Calder" <> wrote:
>>> How are internal rotating assemblies balanced?
>>> And external?
>>> Can a visual inspection clearly tell weather a 408 short block is
>>> internally or externally balanced? (got to answer some ebay q's)
>>> Thanks,
>>> James

Gary Hedlin
98 Sport 3.9 (for now)
05 SLT 4.7

--Many talk about those who died, but too few talk about those who survived... THANK A VET!

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