Quote:
Starting in late 71, 340's were corporate blue until the end of production in 73.


Correct, sometime around March 1971 they changed engine plants from Windsor Ontario Canada to Mound Road Michigan. When the plant change occurred so did the color. Windsor engines were orange, Mound Road engines were blue. Easy way to tell is the assembly info stamped onto the face of the block under the drivers side cylinder head, GW340 = Windsor (Orange) and GM340 = Mound Road (blue).