yes, rpm drop could be a vac leak.
heres a seafoam vid, the guy had his thumb over the hose, as soon as he lets it go it almost stalls till he pinches the hose, you can see the hose sucking in the seafoam too.
your only going to have to bleed the brakes if you need to take the lines off the master to remove the master. some have them flex lines on the master.
what year is this car again?