It had a vibration that came in at about 3500 RPM. It had the round flex plate with the bite section, and the converter had 3 weights on it.
I was thinking this being a steel crank motor with these parts was the cause of my vibration.
There's your problem, if the convertor has weights on it it shouldn't have the flex plate with the "Bite" out of it, it should have one or the other, not both. If it's a forged crank there should be no large weights on the convertor and a completely round flex plate.
Not so fast,
Converters have two types of weights on them. One set, usually on the side, balance the converter to neutral. If the converter is then to be used in an external balance engine then additional weights, usually on the front, are added for the imbalance. A pic would clarify this.
So just having three weights on it doesn't mean it's an external balance converter.
All that said, nothing external with confirm or deny it's a cast or forged crank. You will need to pull the pan. Look at the parting line on the crank, thin line cast crank, wide line forged crank.
