I recently purchased a used 440 six pack setup and wanted to know if it's a nice original piece or a reproduction.
The carb base plate has "Made in Canada" and part number 3418717 stamped on it. Outboard carbs have part number 3462373 stamped in the body and "List 4365-1" below it. Date code looks like 3460

What else can I look for to distinguish between repro and original?

Thanks

Date codes will be the biggest clue but they changed with each decade so it's not a guarantee. Your date code of 3460 indicates that they were produced the 346th day of 1970, but that could also be 1980,1990,or 2000. I picture of the list number will be more helpful. There are other differences too, the hadware and the "Holley" script changed over the years, as well as details on the base plates, but all of those items bolt on and could have been swapped.

.02

Those are factory replacement carbs. 4365 is a rear carb for a 1970 California car N95 the -1 indicates replacement as does the date 3460 the 71s were already in production. I have 4 of those carbs 2 4365 dated 2279 and 2199 and 2 4365-1 both dated 2164.
The front carb would be a 4175 center would be a 4144 for auto and 4374 for manual trans.

What is your application?

2 4365 dated 2279 and 2199 - these should be sent to me for proper disposal

Great info! I just got the setup and didn't have time to gover over it in detail.
Would a carb with a zero in front of the list number e.g. 0-4365-1 be a reproduction carb? I know that some of the reproduction carbs have part numbers, date codes, and list number.

It's a reproduction carb.

Also any carb with the Chrysler 7 digit part number in it is reproduction.

I heard/read both versions about the 7 digit number. Some say the number appeared on several original carbs as well while others say it is strictly on reproduction carbs.

Here's a picture:

Not reproductions, but rather, early over the counter replacements as mentioned by other contributors.