A ? about direct port with inject spacer.
If it is a block, 1st machine it so it fits on the intake, hence most others are smaller all the way around. 2nd, machine in two passages for the fuel and nitrous to flow through, then tap them to accept a jet holder fitting. Look into the three mentioned above to ensure the nitrous&fuel enters at an angle that facilitates good atomization and wont allow fuel to be pushed back up the bung.
Charlie

