Wiz Khalifa Drops 'Taylor Allderdice' Mixtape for 420

Wiz Khalifa's been very active on the music front this year and, naturally, he's keeping that going for 420 ... by dropping a huge streaming treat for fans.

The diamond-selling rapper's throwing it back to his earlier days as a mixtape master, and unleashing his 2012 project Taylor Allderdice (named after his Pittsburgh high school) on streaming services for the first time.

Originally released on March 13, 2012 ... the album had top-notch features from Rick Ross, Wiz's then-wife Amber Rose, Juicy J and production from Cardo and longtime collaborators ID Labs: E. Dan, Sledgren, Sayez and Big Jerm.

Today being a national holiday -- for Wiz, anyway -- he told his 36 million Instagram followers he's celebrating with some Khalifa Kush and a gym session.

The project's host – Genius correspondent and rapper Rob Markman – tells TMZ Hip Hop he was so high out of his mind (how'd that happen?!), he doesn't remember actually saying "It's Rob Markman on Twitter – send ya hate mail" to open the project.

"Wiz had a lot of things to get off his chest and basically told me to ask him any and everything and not to hold back," Rob says. "So we interviewed for well over an hour— Juicy J was there, Smoke DZA was there, Chevy Woods was there, Will was there, and there was a TON of weed. It was a good time."