Big block casting dates.

F is 1970 model year. Assembled 10-2 of 69 for the 70 model year.
I've seen 440 blocks cast in 69 used all the way up for 72 model year. They must have casted a lot of 440 blocks in 69.
How about this one.
It's a 383. 5 / 26 / 71
G383
6. 10. E
What year is E? And what's the G in front of 383?