There are changes in the works. Tonawanda is down right now for retooling. I haven't been able to get any definate info on what they are retooling for but I know they aren't running any 3.5 or 3.9 blocks right now. Also I was looking at some 449 blocks with a hold tag on them. The tag info said they were test blocks. The blocks had both 3.5 and 3.9 cast on the pad. Is 449 a current casting number or will these be a new version?