In 1969, that V8 could be a 327.
Wish I had our old panel back. The stories it could tell......
For the 5 cent knowledge book:
If that engine is really original and a 327, 1969 was the first year for the large journal cranks and all 327s built for GMC that year were steel crank engines (high-nickle blocks too).
The cranks were a hot item in later years to mate with a late model 350 block and build 4-bolt main 327's for class racing.
(ya gotta be an old fart to know this stuff)