I agree with William. I would expect a minimum of 150lbs on a stock cam 71'. Which leads me to the questions about the quote above. Was the whole engine rebuilt or just the heads? How long ago? Does it idle like it has a good size cam in it?...........And one more uncomfortable question.......Are you sure it's a 340 and not a 318 or 360 which would have numbers closer to the ones you got.