SOHC B6 bolt up to the festiva B3 stock tranny?

[drddan]

do i have to use the stock manifold or can i upgrade to the one thats on the b6 motor?

If you have an 89 Festy and 5 spd it should be carb. Is it a carb? The 323 you have is EFI, right? If you have the 323 it should be efi and you cant put a carb on the efi intake.That is why you need to use the B3 intake to mount the carb. Unless you plan on changing the wiring harness and making the Festy efi.
I imagine the efi intake could adapted for carb, but only with modification