Carb models... why diferent allong the years ?

[Nacho-RT74]

Why carbs were changed year by year if they were used on same engines including specs ?

I don't think for example a 69 440 or 383 was to much different from 70 same engines. Same about 72 or 73. or maybe 65/66 engines. I know 74 for example changed the camshaft from an "HiPo" on Magnums engines for a more regular Camshaft, and 71 changed to spreadbores carbs. I also know heads changed on 67, don't knwo if was a real change on performance but the 4 bolts covers changed to 6 bolts covers. And also knows the changes from closed to open heads and hidraulic tappets on 69 from the solid on 68... But we can find SO MANY CARBS allong the rest years.

Were really necessary those carb changes and variety of models with engine changes even keeping same HP and cfms ?

I know different carbs since 72 from 71 specially because the emission controls, but the rest ?

[John_Kunkel]

Many of the changes were to meet emissions standards, even back in the mid sixties.