I have 10k on my 94Z with a 396LT4w/NEW AFR 195's,Comp 987 springs,CC306, comp r lifters, valve cover breathers for pcv system.... for the first 1500 miles there was no smoke at all. since then the problem has steadily become worse in the last 8500miles. First checked the intake manifold gaskets, good (not sucking oil from lifter valley), then a compression test all between 200 and 210psi,plugs are all clean, then a leak dowm test on the cylinders all only 3% leakage.
Does NOT smoke on start up at all. let the car warm up and blue smoke blows out. worse when starting from a dead stop and in between higher RPM shifts. after up to operating temp the smoke contiues to billow out lightly.
I can't belive these new heads are likely the culprit. i checked the geometry and push rod length. the car runs great, not a hiccup, but jsut smokes like the engine is shot!!!
Dustin

 

Probably not guides/seals. Even if you do a compression test/leakdown that can't tell you if your oil rings are bad.
Why do you have a breather if the PCV system is still on the engine? Check to make sure your PCV valve is not clogged.

 

The most likely cause is the valve seals. They can be replaced w/o pulling the heads, so that's where I would start. If that doesn't work, you will need to pull the motor, at least that's what I would do.

Rich