I ran into an issue tonight trying to bolt up my trans. The setup... Stockish 455 with original flexplate. Rebuilt th350 Hughes Gm30 converter. We broke the motor in on a stand a few weeks ago, no issues or wierd vibration. The converter has a ring with 3 holes in it instead of the 3 pedestals like a stock converter has. The ring is making contact with the edge of the weight on the flexplate preventing it from seating fully against it. I have a spare flexplate from a 70 455 and it looks exactly the same only a bit thinner. Both are slightly cupped, or concave. Looking at the marks on them from the stock bolts and converter, the weight faces the transmission. Is this correct? Not only is the ring on the converter hitting the weight but it's very tight. I'm sure the converter is fully seated. Even if it didn't hit, it would be making contact instead of having to pull the converter up to the flexplate. I've not done a lot of these but there is usually a small gap between the two and you "pull" the converter up to the plate. It's almost as if I have the flexplate on backwards but I'm sure that is the way it came off. Input or ideas?