I dont know why would you put a less flowing head B18C on the B16 bottom end unless the B18C(GSR) head is ported and polish and has cames different intake manifold etc. But any ways.Break in your motor at low psi 4,6,8 people I seen run max 14psi on a tune, but dont do that 8-10psi are safe my friends gsr integra pulled a 280whp on 10psi stock motor other then a changed intake manifold.