I don't think I need the retainer. I have a Moroso driveshaft. It has a pinned sleeve on the diameter of the shaft, can't fall out. Or am I missing something here. Also I am not running the HV pump. The HV pump smoked the thrust area on the last build. So is this Pink spring your talking about something for a standard M77? The concensious from what I have read here is go with the standard M77 and run the Blue spring. As someone here said, if that setup was good enough for Smokey Yunick to win the Daytona 500, it outta be good enough for a street pounder. What your guys thoughts on all of this?