Novak does have it, + if you want the Clint Eastwood special ("for a few dollars more") you can upgrade to a positive seal if yours doesn't have one.
Noval SM-420 partsBill is B-3761982-K Kit, retainer, front input bearing, SM420 transmission, billet, GM style
the one with a seal? May just call them tomorrow and check on that.
EDIT: disregard, scrolled down the page and found the info for the seal. Thanks for the info though. Didn't know they could do that.