need help ID'ing a 4.3 engine

[shane]

got a complete 4.3 engine...trying to see what year it came from and what if possible...dont know what it came out of
....on the back of the engine...passenger side of the block is the numbers 10066061 ...on the drivers side ther is a 8SG1....I have googled everyway possible and cant find the info...thanks