993 burning oil after running at 4000+ RPMs 5 min

[RickCrew]

I have a 1998 normally aspirated 993 with a 6 speed manual trans that recently at about 100k miles I had the engine completely gone through. The main reason was there showed a problem in the secondary air injection system. Since that time when every I run it 4000+ RPMs for a least 5 or 10 minutes when I look in the rear view mirror I see heavy blue oil smoke coming from the exhaust. If I slow down with in a few minutes the engine is back to normal and that does not happen again until I run it like above. It never happens if I just run through the gears even if I push the RPMs at or close to the red line. Any6 ideas what to check or what may be the cause?

[917_Langheck]

You're going to need to state what was done in this effort to address the SAI issue (there is no such thing as a standard for "completely gone through" - what does that mean?), otherwise you're just going to get a lot of WAGs that mostly lead to nowhere.