On another note, I'm still getting smoke.

[lmwatbullrun]

I'd appreciate comments on this-

I let the engine idle for at least 5 minutes before I drive it. Very little smoke on start, now that I have spent 2000 miles with various injector cleaning regimens (Lubromoly, ATF, DieselKleen, etc.) Big improvement except for two areas where I still get smoke.

I get gray smoke at low revs, after I have been idling for a couple minutes, such as when I accelerate away from a long stoplight, whether the engine is has been driven a while or not, which I am attributing to fried valve stem seals. (They are 25 years old, after all) Doesn't seem to matter whether the engine's been running for 5 minutes or 5 hours, I get gray smoke after I idle for a while. This can be mitigated somewhat by easing the throttle open; this seems to spread the smoke out and reduce the overall volume somewhat. (I am guessing that the engine is better able to burn the lube oil in that instance) I will probably rebuild a head in the near future to deal with this problem, but would like comments/opinions on my diagnosis before I proceed.

Then, as I continue to accelerate, I start to get black smoke, which seems to come in puffs, from the exhaust. It is notably worse at higher RPM, especially at around 3000 RPM. Rate of acceleration makes a difference, but even just cruising at 3000 rpm, I'm getting black smoke. If I can accelerate slowly, the emissions are much reduced, but not eliminated. This problem is noticeably worse when I have just started driving, and is almost unnoticeable but still present once I have been driving for 1/2 hour or so. I have also had several occasions when this has NOT occurred, and the car appears to have a slight increase in power, too. I do seem to get slightly less smoke generally when I run certain brands of fuel with a higher cetane rating.

I am thinking that this could be several things-
-A diddled with injection pump that is putting out too much fuel under boost. (how does one adjust such a thing?)
-Leaky/fouled nozzles/injectors.
-A control function that is not working/connected properly.
- Bad fuel?
-Something else? (possibly soot being vibrated out of the exhaust from prior problems?)
- A combination of these issues.

I'd welcome comments/suggestions. Right now I am leaning slightly towards replacing the injectors, which have almost certainly never been replaced in over 150K miles/25 years, but would like to have a more definitive diagnosis before operating. Now, keep in mind that when I started driving this beast, I had significantly more smoke than I am seeing now; this is a huge improvement, but still annoying for those behind me and still wasteful of fuel; I'm getting about 29 mpg for a good highway speed 60 mile trip up from 23/24 when I started, and I'd like to get 35, which I think is feasible based on what I have heard.

Thoughts?

On another note, the turbo seems to be spinning faster when I am traveling at highway speeds and ease OFF the throttle; I hear the turbo whine speed up. Is this normal?