Greets All !!

I am my own mechanic on this car, so I hope to reach some
gear heads on this one... ;-)

I have a '81 Buick Regal Ltd, with a 267 (4.4L) and a
Turbo Hydramatic 200/250/350 trans (uncertain which, can find
out if important).  Dualjet-210 Carb.

My problem is generally that the car seems to accelerate
lethargically, and even when driving seems "heavy".  I know
it is an old car, but really it is no heavier than
typical, at around 3200 lbs...  I have done a fair bit of
diagnosing on this and can't figure it out.  A friend
suggested it might be the trans 'slipping'.  Another poster
I saw in here suggested that this problem would slip and catch,
but I am not experiencing that effect.  It just feels 'heavy'
under all driving conditions.  Although accelerating initially
responds ok, there is no hesitation to throttle, but getting
up to speed is laggish.

Any ideas guys?

...

The Details and things I've tried ...

* The trans itself sounds healthy and I have no obvious
reason for doubting the trans.  It Has been a long time
since a fluid change however.  Also I have not done an
accurate measurement, but I suspect the fluid is slightly
over-filled.  However it has ran like this for years, and
has never posed a serious problem.
* The trans fluid itself looks clean and healthy to my
inexperienced eyes.
* Brakes are Not binding, etc!  I have done a Neutral coast
with no problems.
* I have reworked the carb myself and feel confident it is
not at fault.  Even before I touched the carb the car
had the same 'heavy feeling' issue.
* Pretty sure there are No vacuum leaks.
* Possibly related is I see extra deposits on one or two
of the plugs on cyl.7 and 5.
* I do not know the state of health of the valves in
this engine!  This might in fact be my problem I realize.

One day I hope to upgrade to a GN .. ;-)

THANX!!!
Bill