2 Chainz Buys Music Legend's Crib

2 Chainz can rock out in true style ... especially since the crib he bought was owned by legendary rock guitarist Steve Vai.

The rapper plunked down $2.45 million for the 3 bedroom, 5 bathroom Hollywood Hills pad -- which includes the famous "Mothership Studio" where the likes of Van Halen and Ozzy Osbourne once recorded music.

Check out the pics ... 2 Chainz has 3,400 square feet of space to throw epic parties -- if he wants.