I'm pretty sure these are original to the block. the car only has 30K on it, and it was the classic little old lady car. The casting number is correct for a 71 318.
I've been hearing from the machine shops that the ratings for the 360s are just as far off. What's supposed to be a 68cc will actually measure out ot 74 or more cc.
Unless you want to shell out for machine work or pistons, seems like Mopar left us small block guys with one arm tied behind our back.
