When the car was first built, the person who put it together set the fuel pressure to about 8 psi. At my first autocross, I ended up flooding the carb on the first turn 3/4 runs. After that incident I turned the fuel pressure down to 6.5 psi as the youtube video on tuning Holley carbs I watched said 7 psi MAX. I think I may bump it down a little more (5 psi-ish) as, like you're all saying, it seems like its running a little too rich.
Adjusting fuel pressure is not the way to lean out a tune. Too much pressure can push fuel past the floats and through the jets. Once you are below that threshold [7psi], you need to be adjusting idle mixture screws and jetting.
Coolio. I'll watch some youtube videos from Holley to adjust idle mixture screws and jets.
first thing i would do is pull the plugs and see if they are black.
and also set your float level, mid way up the glass if it has that in the bowls, if it's just a screw, the fuel should be right at the bottom if you pull the screw out, engine idling when you check this...
proper idle mix tune won't have the car idling well until it warms up some. tune the idle mix after the motor is completely warm.
go around the carb (all four idle screws) screwing them in 1/8th turn (leaner) until the idle stops getting higher and smoother, then maybe richen it up just a touch from there, like 1/16th of a turn on all screws...
you can also tune the idle mix for highest vacuum reading instead of RPM.
if your plugs are real black.
for the jetting, lean it out in small steps. drive down the hwy steady cruise, maybe 2000rpm, once you are too lean you will feel some very subtle surging. from there jet it back up two sizes maybe.
because of the power valve in the primary side, the seconday jets will be larger by something like 8 sizes or so. (look up the baseline tune for your carb).
