MC Throttle Body problems?!?!

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       Im encountering some problems on my 80 with an MC conversion and k-26
running 14psi of boost.  Possible vacumm leaks and oil leaking from the
throttle body.  The boot between the TB and the IC is good, checked it for
leaks and cracks, the clamp is tight, gasket between the TB and intake
manifold is new and good.  I have even drilled and tapped the small vacumm
port on the underside of the TB and plugged it with a bolt; no leaks there.
Im running the non-vented valve cover off an NG head
       With all of these possibilites out of the way, im starting to lean
towards the shaft that the flap in the TB sits on might be leaking on the
ends, out of the throttle body onto the IM where all the oil gathers.  Has
anyone on the list encountered leaking throttle body shafts??  Cant seem to
find the problem, any ideas would be great.  Thanx

Jerry
-88 80TQ
-91 90