I got a new one for my 454, but it does not have the dual bolt pattern for the convertor. All 6 holes are the same pattern and none of them align to the holes on the convertor. A friend brought a flexplate that came off a 400. It has the external weight like the BBC, but looks slightly different. This plate has the correct pattern to mate to the convertor. Question is; can the external balanced 400 flexplate work behind the 454 without problems? Or are there some differences between the two?