in reference that the B16 head flows better than the b18c one...

The notion that the b16a head flows better than the b18c one is a myth. Both heads have distinct and different flow characteristics, but neither is inherently superior to the other. The overall volume of air moved by either head is pretty much identical.

That said, it may still be in your advantage to throw the b16a head onto the b18c because of the b16's increased combustion chamber volume... it will essentially lower the compression of the motor about 0.2:1.

Are you seriously considering just throwing a turbo on an internally stock motor though? Like I ranted earlier, once the power bug bites, you'll never be satisfied with a stock motor. Anyway, if I were to build a motor for turbo, I'd start with a b18c, bore to 84mm, and leave compression in the 9:1-10:1 range (sound familiar?) Using an LS crank would make a boatload more torque, but that would likely be power you could only use in 4th and 5th gear... And given the high wear tradeoff, I think the b18c crank is a better choice for a turbo motor.

Finally, don't use your motor, I want it! :fawk: