Today I ordered an Eagle internally balanced cast stroker crank for my 383 build. Im thinking a 8" harmonic balancer is needed. Is this statement true? If so what manufacturer balancer is recommended?

 

Nothing is absolute. Use any size you wish ... but most street chevys fare better with the larger 8". If you're building street 383 w/ cast crank ... chances are a $50 8" damper from your local discount parts house will be fine. Brand? ... what's your budget? However, someone else may post that you'll need a $300 fluidamper ... IMHO wasteful overkill in most cases.

 

Be aware that you also need a neutral balance flexplate or flywheel. Stock may have a weight welded on.

 

I agree that an eight inch balancer is a good choice for a street engine
especially on a stroker engine and a three hundred dollar SFI type
balancer is overkill for most people, but a $50.00 dollar balancer
would worry me. Thirty yrs ago I worked as a recieving clerk at an
automotive warehouse and we had a big machine shop on the side
of the building. The parts manufacture sold parts to us at WD
(warehouse dist. price) we sold to the jobber (parts stores) for a
twenty three percent mark up then the parts store marked it up the
most to retail price, thats three companies making a profit. You walk
into a parts store and buy a balancer for $50.00 the original manufacture
may have $10.00 dollars in the quality of the materials in the balancer.
I spend three to four times that amount on my saturday night mexican
food dinner. People spend several thousnd dollars building a 383 engine
then stick a balancer on the front that may have $10 to $15.00 spent
on materials to make it. To me this makes less sense then spending to
much for a $300.00 balancer. If I had $50.00 retail in a balancer you
would not catch my old butt standing beside the car blipping the
throttle or with the engine reved up anywhere. But hell I ran around
with a scattershield on my mostly street driven car, I like my feet
the extra weight was worth it for me.

 

All GMPP 350ci motors (including all ZZ4 & all Circle Track motors) come OE with damper # 88960604 ... 8" ... we see the 602 & 603 CT motors around here alot and rarely see a damper failure (then usually from a hard hit in nose) ... many of the CT motors can go 3 seasons without freshening. CT motors get ALOT of blipping & hard on-off throttle. Equivalent of 88960604 is a $50 parts store damper ... brands such as Dorman & Pioneer. I suppose there's lotsa guys here w/ ZZ4????? ... how many of those have failed dampers? I dunno ... but I don't recall a rash of em.

 

Summit must be like the warehouse I worked at just buys from
the manufacture sells it and at least that eliminates the retail
person. 18 wheeler diesels put off a lot of vibes and out of
around twenty five trucks I have had and put 750,000 to
over million miles on each one I had one balancer go bad on a
cummins, shop forman told me mack, cat. detroit,cummins all use
a fluid style balancer to control the high amplitude vibes. I started
out with mack trucks and have had all the engine brands in trucks.
I think when I buy a balancer it will be at least a one piece street
fluid balancer. At least the outer ring won't be doing any slipping.

 

Try GM for a 8" nodular iron damper #364709 or as Jack already said try a Pioneer. Pioneer makes a nice 8" nodular iron piece for around $80 in the Summit catalog.

As far as fluid dampers go, I can pass on what the guys that run 1/4 mile at the machine shop say and that is they only last for 1 season. Most of them run ATI's.

 

Guys on the forum have had fluid damper on there cars for 10 yrs
with no problem, truck engine would shake a two piece balancer
tell you would never know where the timing mark is, first thing someone
wonders with a used two piece balancer is if the timing mark has changed on them. If the gel inside a one piece truck balancer can
last for way more then a milloin miles with the heavy vibes they put
out I'm going with one of those ONE SEASON balancers.