Hello! Ken at Everyday Performance has a 1242 carb for my '71 GS Stage 1. He said that the production date is late 1970, I think it was November, IIRC. My car has a production code of O3D which I was told indicated a build date in the 3rd week of March. Would a late '70 date coded 1242 carb be correct for an early production '71 car? Generally speaking, how much lag time was there between the carb production and the vehicle's production? I'm still relatively new to Buicks, so I'm not well versed in production dates. Thanks... Chris
No, 71 carb has a huge difference for 455. 71 had much larger secondary bore and was jetted much richer
Generally, production began in the August of the prior calendar year, ie: August 1970 for the 1971 model year. While it's a bit far apart, still perfectly acceptable. There was a strike during the 1971 model year and threw a monkey wrench into production dates, etc. The carb Ken has would work for your Stage 1. As a judge, I would not deduct any points (we don't judge those things anyway in the Buick world).
Brad - Thanks for the comments. Given what Copperheadgs said above, are there any mechanical differences in a late '70 carb vs. one actually produced in '71? Given what you've said about production dates, it seems that a November '70 carb would be squarely within the 1971 production window, and therefore built to '71 specs, please correct me if I'm wrong. If there are any differences, what specifically would they be, ie. 2" secondaries vs. 2 1/4" secondaries(? - just throwing that out there as an example of a difference). This carb ain't cheap, so I want to make sure I'm getting the right one. Last question - should there be a letter code stamped next to the number, ie. MD? It was mentioned in one of my previous posts. Thanks. Chris
The 1242 carb is a 1971 carb, the comparable 1970 carb (1970 455 Stage 1) is numbered 0246 and is a 750 cfm carb whereas the 1242 is a 800 cfm carb. Ken is offering to sell you the correct carb for your application with a build date that is within the range of acceptability. If you need that carb, I would not hesitate to purchase it from Ken. That letter code is quite common.
Ok I misunderstood. It’s not a 70 carb. A 71 carb is a 71 carb no matter when it was made. A 71 Stage 1 carb came with 75 Jets. And 45B primary rods. They were super rich compared to a 70 that had 68 jets. Secondary rods were AU. All those numbers and letters are stamped in the parts.
MD was just a quick ID for a 71 Stage Carb. There was also a round green dot on drivers side front but it’s usually gone.
You have to be careful with buying 71 Stage 1 carbs. GM made some replacement carbs in 1980 to throw in their parts division, so if you look at the date code on them what you think is a date in 1970 is actually from 1980. Does the carb in question have the letter codes stamped into it, or is that area blank? Duane
03D in a 1971 Buick indicates production in the fourth week of March 1971. 03 is the third month (March). D is the fourth week. Jim Vesely ROA # 7437 BCA # 39477
