Most likely if a motor has been tapped for crankcase pressure a pump was used or a fuel regulator.(Perry pump/Cline regulator) Since the tank is placed on CG and the lines are long you might have fuel delivery issues, so a pump or regulator will be needed. You can also move the tank forward to the original position as drawn on the plans and then tap the pipe for pressure for a conventional setup. Is the plane a tail dragger or trike gear?