When Did They Switch to the Internally Oiled Cam?

nope just got pulled off a extra motor i had at my dads house. i have 2 e88 heads but i was not sure what i would need to do for those. i was just going to rebuild one of those and i remeberd i had a extra motor i asked him to look and he said it was a n47 head so i figured to save cash i would use the one off the motor it just needs a good cleaning and mesure to make sure its not out of wack. and try to save the other one in the mean time so i could have a running z.