A bit o' blue smoke at cold idle - 87 4KQT

[Quattrospg at aol.com]

Noticed recently that I get a bit of blue smoke in the morning when the car 
is idling. Very slight amount (you really have to look to see it). Its not when 
you first start the car, but after its been idling for a minute or so. Goes 
away once the car is warmed up and none is observed under acceleration (even 
under boost) or deceleration.  Car runs great. 

I rebuilt the head when I did the turbo conversion, so I doubt its valve 
seals. I have not yet checked compression, but the plugs look great, with no signs 
of oil fouling. There was a fair amount of oil in the intake tubing last time 
I looked. 

Any ideas? Turbo seals? Rings? The JT block has about 220,000 miles on it, 
and the turbo bits (head, manifold, turbo) were added at about a year ago from a 
5KT with about 140K on the clock. I switched to a heavier weight of oil, but 
that didn't seem to help.

Thanks in advance. Any input is appreciated.

Bill