Consider:
Does you exhaust come out the back under the bumper ?
Exhaust is clear but leaves some black. The car is rich still, lean had a different stink. It's also hard to tell what is old and what isn't after I leaned it.
I'm not sure you did read it all.
For being as prickly as you present yourself to be,
you could do with reading some yourself.
To be clear as a bell for 'ya...you notice your response to the question asked has nothing to do with
answering the question?
There is a possibility that your statement of the exhaust being 'clear' means the pipes come out from under the car,
past the bumper so said exhaust is 'clear' from any flow restriction. That interpretation involves a bit of mental gymnastics.
...and the third quote box indeed was not a reply to his question, but a comment from yourself that applies.
If you are concerned about fuel pressure, how 'bout using a gauge to find out what it is? That beats plumbing in a regulator...then you STILL won't know what the fuel pressure is.
A timing light will (can) tell you a lot more than an initial timing number. Where the vacuum can starts the ignition curve, does that affect the idle circuit, what the total centrifugal timing is at what RPM and whether the weights are stuck/sticking...all of those things can effect the smell of the exhaust.
You mentioned having 'tuned' the carb...but no mention of float levels, needles/springs/jet choices. Does 'tune' in this instance mean you fussed with the idle circuit screws? That's not much in the way of 'tuning'.
Transfer slot orientation?
With the car idling and looking into the carb throat, do you see any fuel coming from the wrong places? That can be a dangerous point of view.
What is your idle vacuum? RPM?
Cam? A lopey cam running 6" of vacuum at idle and 10º of initial timing is going to stink.
Exhaust leaks? Headers on the car with what for collector gaskets? Use Remflex exhaust gaskets . As in, period.
New gas, old gas, you don't know gas?
Good luck.