I got clarification of the proper location of the Engine stamping, but I was looking at the format of the 1970 corvette Engine VIN stamping and wondered if you knew if it had changed in 1971 from a 9 digit code to a 10 digit code. The 1970 example was "70S404826" and mine is "C11S116512" for a 1971. I figured the S is for St. Louis and the last six if the VIN of the car. What is the C11 stand for???

Thanks everyone!!!!!!!!!

 

Your format is correct. The 70S number format is not correct and is missing some characters. Careful here. C11 should indicate the 11th day of the third month of the production year. There was a work stoppage at St. Louis in the fall of 1970. If memory serves, the stoppage began in late September, lasted through most (possibly all) of November, and did not resume until the beginning of December. My fiancee has a '71 which got caught up in the stoppage and has a December 3 build date, so production had resumed by 12/3/70. The consecutive unit number of your car (16512) indicates May, 1971 production. What is the Time/Build code of your car?

 

My car build date is J06
Engine ID= V0406CJL
Engine VIN= C11S116512

 

The 1971 Corvette VIN should start with a 1 to indicate Chevrolet. The second number should be a 9 to indicate body series (corvette) and the third number should indicate engine type (even number, usually 4, to indicate a V-8). The 4th and 5th indicate body style (67 convert, 37 coupe). 6th indicates model year (should be a 1) and the S is for St. Louis. Next six numbers are sequential build order.

 

Now we're talkin'. The J06 time/build code indicates the trim tag was attached to your '71 on May 6, 1971 which fits with your VIN. Your car could have begun production the day before (May 5 depending upon the day of the week back in 1971) and probably needed another half a working day or a full day before she was completed. Your car probably rolled off the assembly line on May 7 BUT could have been completed as early as May 6th. Not so confusing when one understands 1971 Corvettes were not complete cars when the trim tags were attached and needed additional time on the assembly line after leaving the station where the trim tags were installed.

V0406CJL indicates a 350 270 hp 4 speed Corvette engine assembled on April 6 (1971) at the Flint, Michigan (V) engine assembly plant. Corvette engines were always in house at St. Louis before production of the vehicle began. Original engines should be dated anywhere from two weeks to a month before the time/build date of the Corvette, so your numbers are good.

The C11 throws me since this indicates the engine was stamped on the assembly line on the 11th day of the third month of production. Most of the time, the third month of Corvette production is typically October, but there was a work stoppage at St. Louis in the fall of 1970 which might account for the apparent discrepancy.

 

Thanks so much for your help!!!! This has been driving me bonkers to figure this out. I was looking at
http://www.71corvette.com/16001.html and it does show Engine VIN numbers and it looks like they all have this C11S like it is: Corvette, Chevy division, 1971, St. Louis. Does this look right to you?

Thanks,

Hunter

 

No, it doesn't look correct, but stranger things could have happened in 1971. As part of your VIN, there are codes to indicate Chevrolet (1) and Corvette (the 9), the body style (37 or 67), etc., but not on the engine pad. On the Corvette engine pad, the C11 is a date code and does not equate to Corvette, Chevrolet, 1971. It stands for the third month of production ([C]. A would be the first month, B the second, and so on), 11 would be the calender date (11th day of the third month of production). On a typical engine during a typical production run, C11 would commonly be October 11th and would mean the engine was stamped on the assembly line that day.

We may need a hand from NCRS folks more versed on 71 numbers than I am to get to the bottom of this. I know there was a work stoppage at St. Louis in the fall of 1970. It began near the end of September (if I recall correctly) and ran through all (or most) of November. Production resumed at the beginning of December. My fiancee's 71 was snagged in the stoppage. Dates codes on her engine indicate her car would have had a late September build date had the line not shut down. Her car has a December 3 build date, which we have determined was very near the resumption of 71 production following the stoppage.

I am confident your C11 code is probably correct for your Corvette and I am equally confident someone on the Forum here can explain the mystery.

 

quoting from corvette 1968-1982 restoration guide vin stampings on early 1971s built in august and early september. after early september the stamping was changed with c11 c represents chavrolet the first 1 designates chevrolet car line and the second 1 designates the 71 model year.no cars were built in october of 70.

 

Your engine was built in the Flint plant (V) on April 6th (0406) and is a 350cu.in./270hp with a Qjet carb and a 4 speed transmission. It was installed in Corvette serial number 116512 which was built in the month of May 1972.

The info from the trim tag on the drivers door post 'J06' narrows the car build date to May 6th, or up to few days afterwards

The St. Louis factory did not stamp the engine pad with anything other than the VIN derivative.

 

Good info.
I'll have to politely take issue with their timeline, though.
My '71 engine's assembly date is VO825 (August 25, 1970) and here is my engine pad:

 

Thanks 694speed350.
HunterPayne -- My apologies for the confusion I may have caused concerning the C11 code. On the commute home yesterday afternoon, I realized it could not be a date code if it appeared on '71 blocks with time/build dates other than yours.

 

MidShark,

Just curious, but your VIN is low indicating early production. With an engine assembly date of 8/25, I would expect your Corvette was slated for mid to late September production. It's possible your car got snagged in the work stoppage. Do you have a late November or early December time/build date?

 

Thanks for the help!!!!!!!!!!!!! I hope that I can return the favor someday.

 

Here are the #'s on the engine ID pad on the 71 coupe I found last summer sitting on the side of the road with a "for sale" sign in the window,VIN#194371S1002412,trim tag build date D24,ID pad is stamped C11S102412 V0901CJK,Black book states car #2412 was built in Nov. but I read D24 to indicate Dec.24th,who knows?????,car does appear to be a "survivor" of all the major components/parts that I have checked only the Alt. does not have the correct code/date #'s for this Brandshatch Green/Green coupe,even was able to reach up on the top of the gas tank and very gently remove the "tank sticker".

 

Yes- my car was a "strike " car. Trim tag date is E 0 3 (Dec. 3, 1970). Plant was shut down from Sept. 15 through Nov. 23.


T0M 65- "D" translates to November (starting with "A" for August, first month for production). In fact , your car was built the first day they were back to work!

Rich

 

Rich,thank you for the info regarding the D24 build date on my 71 coupe,its info that is just nice to know. Tom