I am using a 741CN op amp. I can only get the arduino to output from 353 to +753 when reading from the op amp. I find the limits by putting 5v to each input. If I put 5v and ground to the output, so the arduino is reading 5 and 0, then I get 0 and 1017 as limits, so I know the problem is not with the arduino. The voltage limit on the output of the op amp is 1.2 and 4.0 volts, no matter what voltage the inputs are seeing.
Can you describe what pins are hooked up to which other pins? Even a photograph of your current breadboard/prototype will help as long as all the connections are obvious. Failing that, a hand-drawn schematic could help, even better stick an Eagle schematic up on CircuitBee!