Hello everyone!

I suscribed to this forum because being involved in the old American cars restoration for decades,sometimes some friends ask me a helping hand in their restoration processes.
Now is the case and a close friend is trying to identify the engine from what we believe a 1969 Pontiac Firebird Formula 400.
Here you are the casting numbers we found on different locations:

9792968 Near the distributor
E 149 About the same area
T 402831 Near the timing gear cover
SR 87071

Basically we need to know what year is the engine and if it's a 400 or a 428 C.I

Many thanks in advance!