RetroZone

Not a huge fan of the Tumbler phenomena. Find it a bit self indulgent. Nonetheless, there are a few sites that I follow religiously like RETrOZONe. Here's a small sample of his/her image scans.
Be warned, the site contains mucho, vintage smut

Arnold, Hef and Wilt - 1977

Chiquita and Pedro

Titanic Tina