CamarosRUS

i have a 383 roller shortblock i will be swapping into my originally 305 car and need to know if i can use my 305 flywheel and dampner. the 383 is internally balanced but i didnt know if it would work for sure or not.

jconrad

The flywheel should be the same, I'd think. But I'd look into a larger diameter harmonic balancer.

Confuzed1

iTrader: (4)

So long as your engine is internally balanced, then yes, the 305 flywheel and dampener should work fine. I have a 305 T-5 flywheel on mine now!

CamarosRUS

well if it will work then ill stick with it, im just painting it black anyway but i need to knw it will work correctly. and i didnt want to go spending money on a flywheel because hopefully ill have to put a t56 in really soon

RB83L69

In order to know whether it will work, you HAVE TO KNOW whether your setup is internally balanced or externally balanced. You can't tell that from outside the motor.

As long as you're sure it's internal, then it will all work. If you have any doubt, ask your machine shop, or whoever balanced it, which kind it is.

You'll get better vibration damping with a larger damper. But then you'll have timing mark trouble: in fact, I don't think a larger balancer will even go on over your stock timing cover, because it will hit the tab.

Confuzed1

iTrader: (4)

Yeppers....He did mention it was internally balanced, so it should work. If EXternally balanced, you need to get the flywheel "unbalanced" by a machine shop to 400 specs from what I understand - and use a stock 400 balancer.

I have a larger aftermarket dampener on mine, with a cheapie chrome timing cover and a homemade spot welded pointer on it at TDC.

RB - Whattya mean about the "timing mark trouble"?? Just curious....

CamarosRUS

well the person i bought the shortblock from said he had it internally balanced (and i trust this person) so i guess im in the clear.....if not then ill know right away wont i?

DartByU

Hold on a min. is the 305 flywheel your using from a late model 1-piece rear seal crank? If so it's not going to work, 1-piece seal engines are not internally or externally balanced like the old 2-piece seal engines were, they are a little of both, when GM did away with the extra balance weight on the end of the 2-piece cranks where the seal was they had to add a little weight to the flexplate or the flywheel to make up for it!!! However the harmonic balancer has no weights on it and will be ok to use but not the best choice.

CamarosRUS

i dont understand.......my engine block is a 1 piece l98 block so the extra weight on my flywheel would not work?

DartByU

Exactly, the extra balance weight on a 1-piece seal flywheel would make your internally balanced 383 out of balance, there may be a way to remove the extra weight, I don't know how it is attached, it might could be ground off or machined off, but even if you can remove the weight I would have it checked to make sure it was neutral balanced.

CamarosRUS

ok i just wanted ot be clear my old engine (in the car is a lb9) and the new one that the 383 is in is an l98 block........and i need a new flywheel, which one should i get?

RB83L69

If your new block is also 1-piece rear main seal, which you didn't specifically say but one might assume from mentioning "roller" in its description, then you can re-use your old one.

There's a great deal of confusion about this "weight" on the 1-piece rear-main-seal motors. Yes there is a weight. But this DOES NOT mean that the motor is "externally balanced!! Look at the 1-piece RMS crank flange, you'll see that it's perfectly round, as one would expect since there's a regular lip seal running on it. All that little tiny weight does, is to replace the small amount of balance weight that used to be part of the flange itself on 2-piece motors, which is "internal" to the motor, even though it happens to be located physically outside of the seal. Yes a small portion of the weight is external to the motor; this DOES NOT MEAN that the motor is "externally balanced" in the classic sense of the word.

What I meant about timing mark trouble, is that a balancer larger than the stock one will smash into the stock timing mark welded to the timing cover before it makes it all the way on. So if he opts to get a larger one (which is a good idea if not totally necessary) he'll be faced with an issue to deal with right there.

Here's a pic showing the 2-piece crank flange; you can see that it has that uneven shape to the flange, to create part of the counterweight for the rearmost rod journal. An "externally balanced" motor, which the one in the pic happens to be incidentally, requires ALOT more balance weight than this to balance it.

4BoltMain

I don't think so. a 383 uses a 400 crank, you need the balancer for a 400.

CamarosRUS

well im almost forced to go with a new dampner anyway dont wanna ruin 3500 worth of engine but will my flywheel work correctly......and im also still a llittle confused since there seems to be 5 sides to this equation

im not exactly sure i know what the dampner does to an engine anyway.........or the exact differences of internal and external balancing

but yes it is a 1 piece rms, l98 roller block.....i can get pics if anyone wants them

4BoltMain

these are the parts for chevy SB an BB that are interchangeable

FLYWHEEL
DISTRIBUTOR
LIFTERS

I'm certain your flywheel will work fine man

I'm almost positive that Summit or jegs makes a balancer for your specific application

Chris

RB83L69

This has nothing to do with a big block.

What a larger damper does, is to provide more mass to absorb the torsional (twisting) vibrations that occur in the crank, as a result of the pulsating effect of the application of power from individual cylinders.

Your flywheel / flex plate will work, as long as your motor is "internally balanced" and has a 1-piece rear main seal crank in it. Your damper will also work, although a better one will help to ensure the crank's survival.

If your balance isn't what you've been told, you'll know it the first time you crank the motor up. There will be no doubt in your mind.

CamarosRUS

well i have reciepts (havent looked them over really well tho) and it was a cop so im pretty sure it is, and i know its 1 piece, he gave me the seal, if not ill have his head but a bigger dampner will surely be coming now........now how do i get around it hitting my timing mark tab?

Saigon_Bob

iTrader: (2)

aftermarket timing cover, adjustable timing pointer, remove the ponited on the stcok one an replace with one thatll fit... ect.

jtmiller92

iTrader: (42)

Lol, Use your stock Flywheel. It does have a counter weight on it but is still considered to be internally balanced. When the shop balanced the Crank they made me bring in my Damper and Flywheel to make sure it was right. Flywheel is the same as yours, damper is Neutral balance so if you buy a new one make sure its neutral balanced or from a 1 piece seal crank(also neutral) The crank is a scat internally balnced crank for the 6" rods you have.Later....................................jt

CamarosRUS

hey man i knew youd be around soon well im glad you cleared everything up for me now. cant wait til its in!!!

hows the rs comin?

jtmiller92

iTrader: (42)

Yeah, I almost never check out this board. Usualy looking into suspension and brakes for ideas. The RS is coming along slow but sure. I have everything out of the engine bay to have it painted this Tues. Not really in any hurry to put it back together..........jt

On a side note, I may be parting the 95 Formula I have if your looking for a 6 speed Trans.