Not sure this answers your original question but here is a bunch of info for the 56' 57' and 58' Chevy trucks.
There is a list of engines offered (look under engine serial numbers) by year.
I've bookmarked it for future reference.

http://www.chevytrucks.org/mikesgarage/1956.htm

http://www.chevytrucks.org/mikesgarage/1957.htm

http://www.chevytrucks.org/mikesgarage/1958.htm

"Nothing astonishes men so much as common sense and plain dealing." - Ralph Waldo Emerson