after searching here I didn't find a decent thread with the complete history of weber numbers, dating, changes, etc. ( if someone knows of one please post a link here )
from what I've been able to glean this is what I have so far. webers used in porsche 'production' 911s were:
40IDT3C and 40IDT3C1
1968 911T (non-USA)
40IDA3C and 40IDA3C1
1966 - 67 911
1968 911L (non-USA)
40IDS3C and 40IDS3C1
1967 - 68 911S
40IDAP3C and 40IDAP3C1
1968 911 & 911L (USA)
40IDTP3C and 40IDTP3C1
1969 911T
1971 only 2.2 911T (non-USA)
40IDTP13C and 40IDTP13C1
1970 - 71 914/6
earliest webers were serial numbered ('66 to '70). these numbers may have been tied to the engine or car build or vin number. this number was numerals only. marked 'made in italy' and had the rectangle around the W with an E above it. (sandcast).
after porsche no longer needed webers for production cars, weber went to a number/letter date code in 1970. (sandcast).
later carbs were marked 'italy' and not 'made in italy' and were cast in spain. (sandcast)
last ones were not marked 'italy' at all and were made by carter/USA. these seem to be commonly seen on mfi cars that were converted to carbs in the early '80s. also the weber logo changed. (diecast).
any and all input much appreciated. I'll edit this first post as info comes to light.
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