The swamp should be a go ... Obviously you might have to replace gaskets and seals.... Also check out if your 489 has a large or small yoke and then confirm that the 355 has the same size of yolk... If not it's a no big deal but you may have to get a different type of u-joint or yolk to fit whatever on the end of your drive shaft... I'm assuming you're running stock axles... So a thrust pin I don't think we'll be an issue.. I did just buy a set of axles from Doctor diff and my 391 currently has its thrust pins in I never had to remove them or had any fitment issues...