It's got a B20Z block with a B16 head. I heard B20 blocks aren't boost friendly, so I don't know. I can't afford having my motor blowing on me. I have to drive it in teh snow since this is my DD, trust me, I hate it.clean!!! i miss mine , but i love my sol,lol. y not just boost the b16??? i could not imagine driving my em1 in snow.