All the heads I have seen have had a threaded port on the intake log just below the carb. On earlier auto transmission cars there was a steel line there that went to the back of the valve cover and then transitioned to a hose down to the transmission. On mine I put a T at the end of this line to feed the brakes, dizzy, and transmission. Been running like that for 2 years. On later cars there was a little manifold with several vacuum ports.