Could'nt Pass it by!!

The 403 olds was used in California and the 400 in the rest of the states. I believe you can tell the difference on the shaker or the hood. The 403 was listed as T/A 6.6 and the 400 i think was just 6.6 liter. A little research and you can clarify it. I am just going off memory so i could have them backwards.