I've been considering swapping to an Edelbrock 1406 if I'm unable to get a hesitation issue straightened out with the original Holley. Some here have said that the new 1406's run a little bit lean. My questions are what constitutes "newer" and what does this marking mean? To the right of the 1406 designation there appears a number. Is it some type of date code maybe? Just curious if one of you guys know, maybe @Dana. The reason for the curiosity is considering buying an older one and having it rebuilt.