Vibration in park

[staged67gspwr]

Hi,i am looking to get a 66 GS this guy is selling but there is a problem he cant figure out either,he told me they rebuilt the motor in it and all,but after they had switched from the ST300 to a ST 400 it has a nasty vibration problem at certain rpm`s,what can that be?

Thanks
George

:confused:

[Mark Ascher]

The nailheads are externally balanced, so if they have swapped flexplates around, there might be a problem with that. That's the first thing I would check.

Mark

[Adam Whitman]

George,
I thought I replied to this yeaterday, but must have hit the wrong button someplace...:Do No:

The nailheads can have the flywheel "timed" 6 different ways. Chances are they bolted the flexplate on in the wrong position. I believe there is a hole that you line up to get it in the right spot.

I have also heard that there are different flywheel balances for different year cars, so if they used a different flexplate than what was on the car to start with.....

[staged67gspwr]

I hope so,but the only thing that bugs me is that he said that when he switched from st300 to st400 it started doing it,so he might`ve had the flexplate on right or else it shoud`ve vibrated with the st 300 also right?

George

[Adam Whitman]

I guess the question should be did he change or remove the flex-plate for any reason? Mabe the TH400 coverter hole patterns wasn't there?