Was this 340 installed in a truck?

so since we're guessing at this point, I would guess that the truck came out with a 318 and somebody swapped in the 340 when it was worn out (1980s sounds right) and used the original 318 pan because the car pan it came with didn't fit the truck???

I am intrigued, though, about the possibility that they were putting 340s in pick-ups in Mexico.. It isn't any more unusual than the 318 four barrel factory motors that came in A-bodies sold there....