Issue with stalling when in gear

at what rpm?
is it already advancing?
without the tach it becomes a wild good chase.
with a '67 225 distributor advance begins as low as 650 rpm

Was this done on the fast idle step or the slow?
is the choke on? is the fuel level correct? is the pump shot working?
These are all things I would check based on ppm's post saying its fuel.
Of course I would have pulled at least one plug to see what's going on if I suspected fuel issues that were not obvious (like pump shot)