Carter carbs

[jrcote56@xxxx]

Hi group,
Is there an easy way to determine the carb number on set of carters that have 
the brass carb number tabs missing??
I have what seems to be a matched set that I believe to be off either a '55 
300 or a 300 B but both brass number tabs are missing.
1 . Is there an easy external way (casting numbers or whatever) to tell if 
they are #2317's off a C-300 or a set of #2444, 2445's off a '56 300B.??
2. Anyone know why they changed from '55 to '56 other than to feed another 
23 cubic inches with higher compression?
Thanks,
John Cote