first make sure all tuning and measurement is done with the engine warmed up, a cold verse hot engine is very different and you want to make sure all tuning is down when the car is at normal operating temperature.
next you want to make sure all tuning is down under normal load. in this case foot on brake or parking brake engaged and and for an automatic with the car in gear and headlights turned on.
turning on the headlights loads the electrical system and can affect idle.
so make sure when you tune Idle rpms with an automatic you have the car in gear and hold the brake.
what you will find is you might have a very high park RPMS but you need to compensate for the load down the transmission and accessories can cause with an aftermarket cam.
you are running a huge initial timing. depending on what you are trying to accomplish this could be the problem. Did somebody attempt to vaccum tune the motor?
are you running fixed mechanical for a turbo or super charger?
what CFM is the carb?
what spark plugs are you running?
what are the plugs gapped at?
do you have oem or aftermarket ignition?
what ignition wires are to you running?
do you have vacuum advance?
there are many different ways to approach this but there may not be a solution depending on configuration.
idle bleeds could be out of wack, butterflies could be open too far on secondaries.
on average timing is between 6 and 12 degrees more timing usually means more power but you do throw off the Idle as you increase timing.
now a vacuum leak is possible. you could have a blown diaphragm or a popped off hose or a seal leaking.
with the engine running you could try cupping your hands over the carb intake and choke off the air the engine should stall out, if it keeps running then air is getting sucked in from elsewhere and you usually can hear the vacuum leak.
when testing for a leak, you want to disconnect all vacuum accessories and cap all external vacuum tree feeds to weed them out as possible leak sources.
if you have a hand vacuum pump you can then test accessories one at a time and see what is leaking.
take a vaccum reading with the engine warmed up in gear and get a base line, cap all vaccum lines and retest and see if there was a change.
you can try to choke the carb and stall the engine to check for manifold leaks, if you suspect a leak you can spray around the base with carb cleaner and see if you have a change in idle rpms that would point to a leak.
a PCV that is clogged or incorrect can cause problems, during testing the brake booster, distributor vaccum advance and pcv should be capped off to root them out as a leak source.
if no change then you can move towards tuning changes and away from a leak.
on the tuning end i would back off initial timing check the ignition system for problems and inspect the mechanical advance to make sure it is operating correctly.
then all tuning would be under load, lights on car in gear.
when i first started to tune my car i was getting 13" in park and 7-9" in gear.
i had to change plugs, coil, ignition wires, i changed to points during testing.
i also had failures in parts i thought were good and turns out not to be.
i had to replace my brake booster, and A/C vacuum canister as they caused problems.
I found i had ignition problems even with new parts.
then it came down to setting rpms under load. on my car i have to run over 1000 rpms in park because it drops heavy under load down to 700-800rpms.
when you rebuild engines and go with aftermarket cams you can take the ford oem specs on how the engine should be setup and throw it in the trash can. you have to go by what your engine is telling you.
in your case there are still many questions, and then there is the direction you want to go with the car, tuning for traffic and normal street driving is different from performance and there is trade offs.
