[Formulajones]

Originally Posted by Kenth

Front lower passenger side in throttle plate is the EGR port, this port is too weak for the ignition vacuum advance since it is a bleed off port.
However, it can be used if the bleed off hole/slot is closed.

The regular port for ignition vacuum advance is on drivers side, right above the idle mixture screw.
This port is for most units ported/timed, and for others it is a constant vacuum port, check location of slot, if below blade it is constant, if above it is ported.

Correct, there are some units that simply don't have a ported source for the vacuum advance.