take the sparks plugs out...remove valve covers off...spin engine...see if oil is coming out..

or removed rocker shafts...and watch for oil squirting out of shaft mount....

TA shafts from the factory are groved...

the notches on the end of the shaft should point down and towards your left as you look at them...

driver side...down and towards front of car..
passenger side ...down and towards firewall

other thing that is possible is that a cam bearing has spun or is not correctly installed as the oil to the heads are fed from cam bearings 2 and 4.