Where can the Misc 51% parts come from?

[Racegunz]

In a recent chapter meeting a subject came up about using parts from scrapped or parted out Certified airplanes, and a "new" rule that you could not do so. I thought for a minute and thinking logically I said how would anyone ever build a Breezy? don't they typically use wings from parted out planes. Answer: they have to scratch build them now. Hmmm, not buying it but being a brand new member and not wanting to just say B.S. I said well where is the line drawn? can I use a formerly certified Lycoming? or a slick mag? or must all new homebuilts be kit aircraft with Rotax's or VW conversions ect. Answer: well it depends on the DAR. ????? I' read the AC 20-27g and it seems pretty clear on using certified parts,what say you EAA forum?