Correct carb dates for 69 L-71 auto

[Kenneth K.]

Hi everyone -

Does the 6-month window apply to the Holley tri-power carbs on a 1969 L-71 automatic? And if so is it from the date of manufacture or date of the engine.

I am ready to have my end carbs restored but don’t want to if they are not the correct dates. I will purchase the correct dated carbs already restored if that’s the route I need to take.

Here are the dates:
Door tag shows manufacture date M28 (August 28, 1969)
Engine assembly date T0325LX (March 25, 1969)
End carbs 3659 date 981 (1969, August, first week)
Center carb is 4055 (incorrect). I will need to find a 4056 with the correct dated.

Thanks,
Ken

[Terry M.]

Hi everyone -

Does the 6-month window apply to the Holley tri-power carbs on a 1969 L-71 automatic? And if so is it from the date of manufacture or date of the engine.

I am ready to have my end carbs restored but don’t want to if they are not the correct dates. I will purchase the correct dated carbs already restored if that’s the route I need to take.

Here are the dates:
Door tag shows manufacture date M28 (August 28, 1969)
Engine assembly date T0325LX (March 25, 1969)
End carbs 3659 date 981 (1969, August, first week)
Center carb is 4055 (incorrect). I will need to find a 4056 with the correct dated.

Thanks,
Ken

Ken

The carburetors were installed at St Louis. The AIM shows the part numbers. All items with part numbers shown in the AIM were installed at St Louis. Thus the six month window for the carburetor dates is from the body build date -- August 28 in your case.

As far as I know 1969 carburetors are not an exception to the six month rule of thumb, however a message to the 1968-69 Team Leader (Bob Demmel) would yield a more authoritative answer than my limited knowledge.

[Kenneth K.]

Hi Terry-

Thanks for the advice. I definitely will ask Bob. I asked Hans Norberg this question in 1993. He said that was a tricky question because on extremely low production items (by GM Standards that is 1000or less) an initial order was placed and then more ordered as needed. For his 1971 LS6 there were only 212 built. GM made an initial order of 100 - 150 carburetors so all but the end of production have the same early date for the carburetor and some cars have original dated carburetors far beyond the 6-month window. My end carburetors are within the 6-month window so it’s probably not an issue but I plan to ask Bob anyway.
I didn’t realize that all items with part numbers in the AIM were installed in St. Louis. It makes sense but I never really thought of it before. I notice the oil filter is shown in a diagram in the AIM but it does not have a part number associated with it. That supports my guess that the oil filter was installed at Tonawanda after the engine test that Duke described. I suspect the filter was installed without any oil.

Can you or anyone else recommend a restorer I could send my end carburetors? Also any advice on a reputable person that might have a 4056 center carburetor I can purchase?

Thanks,
Ken

[Leif A.]

Hi Terry-

Thanks for the advice. I definitely will ask Bob. I asked Hans Norberg this question in 1993. He said that was a tricky question because on extremely low production items (by GM Standards that is 1000or less) an initial order was placed and then more ordered as needed. For his 1971 LS6 there were only 212 built. GM made an initial order of 100 - 150 carburetors so all but the end of production have the same early date for the carburetor and some cars have original dated carburetors far beyond the 6-month window. My end carburetors are within the 6-month window so it’s probably not an issue but I plan to ask Bob anyway.
I didn’t realize that all items with part numbers in the AIM were installed in St. Louis. It makes sense but I never really thought of it before. I notice the oil filter is shown in a diagram in the AIM but it does not have a part number associated with it. That supports my guess that the oil filter was installed at Tonawanda after the engine test that Duke described. I suspect the filter was installed without any oil.

Can you or anyone else recommend a restorer I could send my end carburetors? Also any advice on a reputable person that might have a 4056 center carburetor I can purchase?

Thanks,
Ken

Ken,
You can send your carburetors, with extreme confidence, to Phil Cancilla @ Custom Rebuilt Carburetors (732)-356-4333. His restorations are exquisite. He may, also, have a 4056 center carb for you.

[Kenneth K.]

Thanks Leif!

[Mike E.]

Hi Terry-

Thanks for the advice. I definitely will ask Bob. I asked Hans Norberg this question in 1993. He said that was a tricky question because on extremely low production items (by GM Standards that is 1000or less) an initial order was placed and then more ordered as needed. For his 1971 LS6 there were only 212 built. GM made an initial order of 100 - 150 carburetors so all but the end of production have the same early date for the carburetor and some cars have original dated carburetors far beyond the 6-month window. My end carburetors are within the 6-month window so it’s probably not an issue but I plan to ask Bob anyway.
I didn’t realize that all items with part numbers in the AIM were installed in St. Louis. It makes sense but I never really thought of it before. I notice the oil filter is shown in a diagram in the AIM but it does not have a part number associated with it. That supports my guess that the oil filter was installed at Tonawanda after the engine test that Duke described. I suspect the filter was installed without any oil.

Can you or anyone else recommend a restorer I could send my end carburetors? Also any advice on a reputable person that might have a 4056 center carburetor I can purchase?

Thanks,
Ken

Ken,
Your LS6 numbers are a bit inaccurate. There were either 188 or 188 +12 LS6’s made. We still don’t know if GM’s production number of 188 includes the 12 ZR2 cars or not. There is no basis for a 212 number. You are right in that GM made a substantial early initial carburetor run, but any attempt to put a quantity number on those is pure speculation. Comparing the L71 and LS6 situations is a bit dicey, because GM anticipated producing LS6 cars throughout the production run, but the first one actually didn’t roll off the line until March 1 (and had a February 26 trim tag). Most likely the delay was due to federal emissions qualification.
Good luck with your carb quest!

[Kenneth K.]

Hi Mike-

Thanks for the clarification for the number of LS6s built. I got my numbers from notes I took in a conversation I had with H. Norberg in 1993 so they are outdated.

Hans also told me he wanted to do a survey to find out more about the dates on the carburetors for the 1969 L-71 automatics but sadly I believe he passed away before he could accomplish the survey. At that time in 1993 he thought there were either 256 or 257 cars built in 1969 with the l-71 automatic. Do you have more recent data on the number of 1969 L-71 automatic cars built?

Thank you,
Ken