68Blkbrd, the quickest , (but not always reliable) way is to check the color! baby blue or metallic blue are Pontiacs, Chevys are orange... its reliable if not re-painted...
my 400 pontiac came bright yellow (obviously re-painted! ) but the location on the block as PMI states in his 5): " Two letter code stamped on the front of the passsenger side cylinder bank, along with the four-character date code next to the distributor hole define the size and factory rating of the motor. The date code is a letter followed by three numbers. The last number corresponds to the year, i.e 9 is 1969 or 1979" is a good way to tell...
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