Early small diameter EL flywheels. After installing the shafts correctly, always true each 1/2 and check for run-out on the flat side of the OD. .007 or less is acceptable. Sometimes it's tough to get it. Then mark them so you know where the high spot is when truing the finished assembly. High spots near the crank pin aren't so bad - since when the motor fires and pushes the rod down - it's kinda like truing it up perfect for a brief moment - That's my thinkin' and I'm stickin' with it . . . Gordy will be proud !