horrible vibrations as you rev the car and no vibrations at idle

[buening]

That would really make me wonder what the internals are balanced as? I'd guess 50 oz, and they used the original balancer to use with the original crank pulley and v-belts.

Me too!

 

[Arto65FB]

1 Vibrations, you got 50oz flexplate and 28 oz damper, you have to tear down to see if flexplate imbalance has been tampered to make it 28oz if not and it really is 50oz, you found the culprit. Next drop the oil pan and find out what crankshaft you got if 28 oz imbalance, you need a new flexplate with 28oz imbalance or if it is 50oz crank, you need a new damper with 50oz compatible damper (iirc, the damper imbalance is actually 34oz or so, but everybody talks about 50oz).

2 Starter shims, I have done that too. There are two starter noses, one for early manuals and one for automatics. Part numbers are mixed in many places and they send you wrong one. I found it easier to shim it than order another one.

 

[GT350]

1 Vibrations, you got 50oz flexplate and 28 oz damper, you have to tear down to see if flexplate imbalance has been tampered to make it 28oz if not and it really is 50oz, you found the culprit. Next drop the oil pan and find out what crankshaft you got if 28 oz imbalance, you need a new flexplate with 28oz imbalance or if it is 50oz crank, you need a new damper with 50oz compatible damper (iirc, the damper imbalance is actually 34oz or so, but everybody talks about 50oz).

2 Starter shims, I have done that too. There are two starter noses, one for early manuals and one for automatics. Part numbers are mixed in many places and they send you wrong one. I found it easier to shim it than order another one.

will check flexplate properly when i drop the trans,although looking underneath the flexplate has 50oz written on it with black ink and its a new one with a sfi sticker