***EDITED***
WIth that small a cam it should be pulling double that vacuum at idle.
This should all be done with the vacuum advance disconnected from the distributor and the hose plugged.
Step one - up the initial timing to 18°.
Step two - Using a "dial back" timing light, or a balancer that's fully marked, or a timing tape on the balancer - Check total timing by slowly bringing up rpms until the timing mark stops moving - then go another 1000 rpm higher and note highest total timing. You should have something like 38-42°. You will need to adjust the centrifical advance slots to limit centrifical to 32°. Directions for this are online or in the instructions with the ignition.
Step three - Reset the idle mixture to highest vacuum level noted and idle speed back to 750 (it will have risen a bit with the extra initial timing).
Step four - take a new vacuum reading.
Step five - Take that new vacuum reading and: if it's over 12" - make sure power valves are both 8.5. If it's lower than 12" divide the number by 2 and install that in both positions.
Step six - reset idle mixture and speed, reconnect vacuum line to districutor, and test drive. My impression is the power valve(s) are opening at idle, and the mixture screws are out too far, but timing curve and adjustments should always be done prior to any carb work and MP ignitions are famous for being a mess out of the box - so check/address the timing first, then tune the carb.
