need exhaust manifold casting number

can anyone give me the casting number for the driver's side manifold on a 383 barracuda (the wierd looking one). apparently there was the original one first brought out that was 2 1/4" outlet, then in June of 1967 they brought out another improved one that was 2 7/16" that allowed more cooling and 15 more horsepower. i'd like to have both numbers if possible, so i can differenciate between them. the number i have located so far is 2946728, but i'm not sure which one that is. many thanks Gerry