vladss

you guys with lt1 383's...
Do you guys use a Stock Flywheel? Im Told the stock lt1 is external balance at the flywheel and the 383 is internal and needs a neutral balanced flywheel.

Anyways, I have a bad vibration at 2500rpms on up and I think its the flywheel. I dont remember a Vibration when the car was an auto...

fergymoto

iTrader: (129)

You were told right. That is what happens when you have the wrong flywheel/flexplate.

SS RRR

iTrader: (2)

That needs to be fixed before you turn the key again or it will become expensive. I use a stock flywheel, but had it zero balanced from the machine shop before I installed it...

James Montigny

iTrader: (13)

If your 383 was neutral balanced, it's an easy fix. Just get a neutral flywheel.
If it was not, you have to take it apart and start over.

The 355 I bought back in March taught me that lesson.
I should have taken it apart and had the balance checked before I installed it.
That fiasco cost me a whole race season.

The new 383 is neutral internal with a neutral SFI-approved flexplate

vladss

I had the whole thing balanced with the Flexplate when it was still an auto. Afteri got It running I Switch to 6-speed with a stock flywheel. I had the clutch and flywheel zero balanced but i still get a BAD Vibration at 2500+ RPM is there anything else i should check? maybe the flywheel is not true?

BALLSS

Your 383 is most likely "neutral" balanced aka "internal". If you run a stock LT 1 flywheel it is for "external" balanced aka "stock" motors.

Pull the flywheel and have it zero balanced at a machine shop

James Montigny

iTrader: (13)

You need to have that flywheel matched to the flexplate you used in the original balance work.
Look at the flexplate, there should be marks on it indicating what was done.
Or take it to a shop and have them tell you.
That will give you an idea of what needs to be done before you pull your flyeel off.