Hey new to the six pack world here. What is the difference between the 2946275 and the 2946276 440 six pack intake numbers. Is one a part number and the other a casting number as I suspect. Also on a 1970 V code Charger with a November 21 build date what date code of intake should I be looking for. Thanks in advance.

Cast Iron for 70, both numbers you have are casting numbers for the 2 cast iron manifolds offered during 1970...2946275 is an early casting for 1970, casting #2946276 was used later in 1970 production, 276 was a retool, as the early iron manifolds (275) had casting issues