C3 1970 LT-1 - NCRS Discussion Boards

C3 1970 LT-1

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  • Jim T.
    Expired
    • March 1, 1993
    • 5351

    C3 1970 LT-1

    The following is from the fall issure-1983 of Corvette News Tech Questions & Answers.
    Q I recently encountered an individual selling a 1973 Corvette coupe, who claimed he had an original LT-1 which was supposedly available by special order early in the 73 model year. Did Chevrolet ever offer RPO LT-1 during the 1973 model year.

    A No. In the 1973 model year, the solid-lifter LT-1 engine was replaced by the hydraulic-lifter L-82, but the LT-1 was available to dealers as a completely assembled item, sans carbururetor and fuel pump, in 1973. We knew of dealers who did install the LT-1 in post 1972 Corvettes which then sold with zero miles on their odometers. Ther service part number for those LT-1's is 3965784. An additional check: look for the three-letter suffix XCJ where the engine number appears on the block near the water pump, indicating the engine was probably dealer installed.

    Q I purchased a 1970 LT-1 Corvette in June of '82. The original owner advised me that a replacement short block had been installed under warranty. The replacement engine number is CEA137600. Would you be able to verify that this is a replacement LT-1 short block.

    A There's no way to verify it from the outside. CE indicates the Chevy Engine Plant-Flint, the A137600 indicates it was made January 13, 1976. Check the oil pan rail section for a six to eight digit number which would help narrow the verification process, since the number you supplied isn't conclusive. Or, next time your engine is apart, check the forge number under the pistons. These numbers can be verified at your Chevrolet dealer for your answer.

    Q I own a 1971 Corvette with a CJK engine designation. Some say it indicates a higher horsepower option than the base engine for that year, but short of the LT-1. Can you help clear up the confusion?

    A Our part number guro took a gaze into his crystal ball and found the CJK designator identifies the 1971 350 cubic engine, rated on page 14 of the March '83 Chevrolet Dealer Parts Book at 330 horsepower. It also indicates your car should have the THM400 transmission.
  • Chas C Henderson

    #2
    Re: C3 1970 LT-1

    I believe the CJK question has come up before and the answer was they are all 270 hp, engines. I wish they were 330 hp. My 71 does have the TMH400 tranny.

    Chasman

    Comment

    • Joe L.
      Beyond Control Poster
      • February 1, 1988
      • 43193

      #3
      Re: C3 1970 LT-1

      Chasman and Jim-----

      Yes, it looks like their "guru" had a faulty crystal ball. The "CJK" code was used for 1971 Corvettes with 270 hp 350. It was not used for any 1971 LT-1, Corvette or Camaro. Besides, the 1971 Corvette LT-1 was never manufactured in a configuration for use with THM-400 transmission.
      In Appreciation of John Hinckley

      Comment

      • Dennis D.
        Extremely Frequent Poster
        • March 1, 2000
        • 1071

        #4
        Re: C3 1970 LT-1

        Is that code deciphering right? How about CEA129749, with a L 29 0 embossed on an 010 block?

        Comment

        • John H.
          Beyond Control Poster
          • December 1, 1997
          • 16513

          #5
          Re: C3 1970 LT-1

          Dennis -

          The block of numbers for "CE" blocks assigned to Flint V-8 was 20,000 to 49,999 (per April, 1969 Chevrolet Service News), and that much fits; decoding of the "A" and the "1" prefixes is less clear (never published, not part of the "standard" stamping format for "CE" blocks), but with a December-cast block, either one could relate to January.

          Flint V-8 did some strange things with non-standard "CE" block coding/stamping; the one in my '69 Z/28, cast in May, 1970, and installed in June, 1970, is stamped CE 0A965 0 9.

          Comment

          • Dennis D.
            Extremely Frequent Poster
            • March 1, 2000
            • 1071

            #6
            Re: sequence not date?

            John....

            Sounds like your saying the number is not a date code as the article claims, and others have suggested, but more a sequence number.

            Comment

            • John H.
              Beyond Control Poster
              • December 1, 1997
              • 16513

              #7
              Re: sequence not date?

              Dennis -

              The Chevrolet-published standard stamping format for "CE" blocks identifies the first digit (a number) as the calendar year it was produced, and the following number digits as the production sequence (within the assigned block of numbers) for the number of "CE" blocks produced at that plant. The many other non-standard "CE" stamping formats utilized have yet to be "decoded".

              Comment

              • Dennis D.
                Extremely Frequent Poster
                • March 1, 2000
                • 1071

                #8
                Re: sequence not date?

                John
                Assuming the blocks were first cast and at some later date, numbered upon assembly, would there have been a rational or reasonable, "cast vs assembly" time frame?

                Comment

                • John H.
                  Beyond Control Poster
                  • December 1, 1997
                  • 16513

                  #9
                  Re: sequence not date?

                  There probably would be, but there is no date indication in the (standard format) "CE" pad stamp other than the calendar year of manufacture; the only other date information is the casting date of the block on the rear flange.

                  Comment

                  • Dennis D.
                    Extremely Frequent Poster
                    • March 1, 2000
                    • 1071

                    #10
                    Re: sequence not date?

                    John...

                    I'm a little slow in my old age. You reference the 20,000 to 49,999 CE units. Would they not have been stamped in order?

                    Oops, think I answered my own question. Lets see if I got this right. Unit 20,000 could have been, lets say... a Jan.1 70 assembly. No units for 6 months and then 1000 units in a couple of days,skip a week, assemble some more, etc..... No way to determine exact dates since the units weren't assembled from 20,000 through 49,999 non stop, day after day, X amount of units per day.

                    Am I getting it now??

                    Comment

                    • John H.
                      Beyond Control Poster
                      • December 1, 1997
                      • 16513

                      #11
                      Re: sequence not date?

                      Yup, you've got it - "CE" blocks were built in batches as they were ordered by GMPD, and were run on weekend overtime; the high-volume production equipment on the end of Line #1 and Line #2 couldn't handle blocks with no heads, intakes, or oil pans, and they had to be handled manually.

                      Comment

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