Drive train Vibration

[basement]

So, I got my 4-speed back from the rebuilder (new input and output bearings, and cleaned up the shift from 1 to 2nd) and put it back in my 360 challenger. At the same time I also replaced the clutch/pressure/throwout bearing, and flywheel and replaced the plastic bearings in the Z-bar. Now I am feeling a vibration at 3krpm and above in any gear. The vibration isn't near as noticable when I am stopped and in neutral but can't be sure. I think it might be one of two problems. Either the drive shaft is in 180degrees out, though I didn't think it mattered. Or the flywheel. If you saw some of my previous posts I was confused on what flywheel to purchase and ended up going with the 130tooth, 360ci version with the 3-large holes on the engine side of the flywheel, though it was visibly different from the one I pulled out. If it was the wrong flywheel I'd think the vibration would be pretty tremendous at all times?

[heminut]

I would say you have the wrong flywheel in there!

[ShelbyDogg]

I say that if the old flywheel didn't have the 3 big holes on the back, somebody had your engine balanced with a neutrallly balanced flywheel on it and added metal to your crank.  The one with the 3 holes was for the stock externally balanced crank.  Does your harmonic balancer still have it's offset weight on it?  The other owner might have opted away from the externally balanced stuff, and used 318 or 340 stuff.   Put your old flywheel back on or have a balance shop tell you how it was weighted. You can have another flywheel balanced to match your old one if it isn't a neutral flywheel.

[basement]

I've never inspected the harmonic balancer that closely other then when timing the engine, are the offset weights simply welded on and easy to spot?

[ShelbyDogg]

The 360 stock balancer had more weight to one side of it instead of looking even all the way around.
It might even be marked saying "for 360 cast crank only".   If it didn't vibrate before, just work on the back end  and don't worry about the front.  You still have the old flywheel, don't you?

[basement]

Yes, still have the old one but it was extremely cracked all over and the machine shop guys wouldn't attempt to resurface anyways. I've attached two pics, the jpg is what came out of the car and the PDF drawing is the new one I installed.

[ShelbyDogg]

Lots of different holes on the new one.   This is what my balancer would do.    He would put your old flywheel on the balancer and see where the added (or offset) weight shows up and record it.  He would then balance the new flywheel to match the old one.  Yours already having the 3 big holes could be a problem.  You might have to start over with a new one.

Have your balancer look at the old one first and go from there before taking the car apart.  I wouldn't drive it though until the balance is fixed.  You could ruin it.