[carhodge]

building a 383,is it ok to use a 6/34 instead of the 8in...?

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67ssclone 327 4spd 410

[Everett#2390]

You can use either one, both have pros & cons.

6 3/4=faster to RPM, but will not absorb as much of the harmonics as 8 inch will. Has less kinetic energy than 8 in., think in terms of a flywheel.

8 = slower to RPM, but, reduces the amplitude of unbalance more than the smaller one.

For all practical purposes, 6 3/4 is good for the street and weekend duty. However, think of the 302, they came with 8-in., but then, they were made for 7-9K RPM.

Others here may have some good thoughts about this subject.

Everett 68/350/PG/11.90115mph

[Grape Ape]

In every test I've seen that swapped dampers (stock type), the larger ones always showed more power, even in acceleration tests. This tells me that even though the 8" is heavier, it helps in other ways to reduce power losses and in the end will make up for it's weight.

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www.grapeaperacing.com

[427TRI]

I use stock 8" on my spinning 427. I wouldnt go smaller unless its a drag car only.

[JohnZ]

You don't have a choice, unless you've spent the money for Mallory metal to internally balance your crank. Otherwise, you have to use the 8" 400 balancer, as it is offset-weighted for external balance (you also have to use an offset-weighted flexplate or flywheel with it).

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JohnZ
'69 Z28 Fathom Green

[Everett#2390]

Some very good answers here, from all of you,

Your input on type of harmonic balancer to use?

Everett

[camaroman7d]

Hey JohnZ they make internally balanced 383 cranks now, so you don't have to run a 400 balancer (if you buy a internally balanced crank). Also there is no need for mallory metal with these cranks. Just thought I would point that out.

Royce

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70 Camaro 383ci
69 Camaro 385ci
91 Camaro RS V8 (305 TBI)
Link to my 70

http://profiles.yahoo.com/camaroman7d

[carhodge]

Thanks guys,I think I will go with the 8".

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67ssclone 327 4spd 410

[b-boy]

Johnz, You don't have a choice? I am using a 6.1" (that's right, 6.1") balancer on my 383 with no problems. It's from BHJ Dynamics inc., and is a ductile iron (nodular) hub and ring. It comes with 90 degree marks, 0-50 degree timing marks and "failsafe" ring mounting. It was $109, not much more than a stock unit and a whole lot better, in my opinion.

[pdq67]

Doesn't somebody make aftermarket 400 SB and 454 BB dampers w/ bolt in weights so that they can be used w/o the weight on an internally balanced engine and w/ the weight for an externally balanced engine??? pdq67

[Lonnie67]

pdq67, check out the ballancers at www.flatlanderracing.com I think they have what you want.

Lonnie

Oops, maybe not. I know I've seen them somewhere.
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67 Camaro 410sb 11.63 @117.6
67 Camaro 388 12.10 @110.6
website

[This message has been edited by Lonnie67 (edited 08-08-2001).]