Read up a bit on the green bearings. See Link:
http://www.bigblockdart.com/techpages/875axle.shtml
From Section 5:
Green Bearing Company builds a bearing kit that replaces the cone-type wheel bearings. These are sealed roller bearing units that do not require end play adjustment, however they offer no side to side support, and fail quickly in street applications. These are drag race bearings only (the manufacturer even lists them under the "Racing" segment of their catalog). Green Part No. RP400.
Anyone using these bearings ever have problems?