As far as numbers ... there's a 2-letter code by the carb #, that actually describes which car it goes to. I think what you're describing is 7029207? That same carb goes on Camaro, Chevelle, Nova, etc. The 2-letter code would match the build sheet and model of car.
There's also a date code underneath the carb #. Typically a 4-number Julian style. First 3 numbers are day of the year, last digit is the year.
FYI, 90% of the one's I look at are service replacement carbs. Easiest way to tell is the date code ... they obviously didn't produce a '69 model carb, in a year ending in 1, 2, 3, etc!
Another one (I can't seem to prove it), but all original carbs I've seen do not have the "70" in the carb #. They would simply be stamped 29207, etc.
Here is some help on 69 Q-Jets. It does get involved so if you end up not understanding, please ask again and I will try to clear it up.
There are two manufacturers of Q-Jets. Both Rochester and Carter made them. Each has its own unique stamp and dating type. I will begin with the Carter, as it is the easiest. I will stay with 69 year info as this is the year in question.
All 69 Carter produced carbs are dated with a two line stamp. Number starts at the top of center body and is stamped vertically on the pad. it is then followed on the same line by the two letter assembly, or build sheet code. This is what would appear on a build sheet, and was used to choose the correct carb. The date on Carter Q-Jets was two digits on the next line below the part number. It was a month and year only, A-M for month (Skip I's), and single number for year, in this case, 8 or 9. I have yet to see a #7029207 as a Carter carb, but they are common in other 69 Q-Jets.
Rochester Carbs were definately in transition this year, and used three different types of stamps.
1) Early year Rochester Q-Jets used the whole number stamped in one line including the build sheet code. The #70 was definately used. Number started at bottom of center body. Dates were stamped on the base on the side just behind the secondary throttle shaft on the drivers side. Dating was four digit Julian Date (ex: 3658= 365th Day of 1968) We have also found many of these early types of carbs with no dates on base and believe them to be real. Seem to be on cars between Nov-Jan, but for ovious reasons, cannot confirm starting and ending date of undated carbs. I believe the latest base dated carb I have had was about the end of the year 68.
2) Later 69 Rochester Q-Jets are dated all in one line, and the number, build sheet code and date are all on the vertical pad. Same type of dating as before, and because there was now more info, the 70 was left off as Neal reported. Earliest one I have seen with this type of stamp was 3638, but again, I cannot confirm when it started, and some overlap with the earlier numbering type is possible. This type extended into early 1970 production, when a two line stamp replaced it, which was similar to the Carter type.
3) There is an extremely rare mid year stamp, seems to have been used from late Jan, thru Feb. I cannot again confirm starting and ending dates on this type. It was a real small print with all info on one line and the full part number used. Fonts were about half the size of the normal Q-Jet numbers. I have had these in #7029207, #7029203, and #7029201 and #7029215.
By the way, the Corvette lists the #7029204 for 390HP AT, and #7029215 for 390HP Man. The #7029200 & #7029201 are for 325 HP Chevelle/Camaro/ and have Full size and Nova use, but not Corvette. The #7029207 mentioned in this thread is Corvette 350 350HP. Do not listen to applications listing this for Chevelles, they are wrong. Chevelles used a 300HP motor with the #7029202 on At, and #7029203 on 4spd. Also, as Neal said, the #7029207 was used for many years as a service unit, and sold over the parts counter. It is probably the most common service carb ever made, as they would make only one number, and use it to replace #7029202, and #7029203, etc. Did not matter as much, since it was a replacement. Also, these exist with dates in 78 and 79, and will have a date that will fool you into thinking they are 68 or 69, since they end in 8 or 9. At this point, one must know various features about the carb that ID it to tell the difference. Dead givaway is if it has a pad on center body to mount an idle stop solenoid. 69 carbs did not have this pad. Also, they made this carb in 80's and 90's, since it was one used in NHRA approved racing. 80's up #7029207 carbs have a number of #07029207. I can almost assure you 99.9% of the #9207 Q-Jets you will find are service. I have only ever had 5 production ones in 20 years!!!!!
Hope this helps you guys decode your carbs.
Diamond Restored Judge