1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank - NCRS Discussion Boards

1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

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  • Joe L.
    Beyond Control Poster
    • February 1, 1988
    • 43199

    1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

    I'm starting a new thread on this because some recent discussion on this topic was done as part of another thread relating to LT-1 fuel lines.

    There is no information in the 1971 AIM relative to the above referenced topic components. The information that I've been able to glean from SERVICE parts info (which, by the way, originates from PRODUCTION information) is a bit vague. In any event, it would seem that 1971 LS-6 was originally equipped with an AC type 40770 fuel pump. This pump has provisions for fuel return. It would then follow that the LS-6 equipped Corvettes were also equipped with a fuel return line co-located with the fuel supply line and a fuel tank with provisions for a fuel return line on the upper right side of the tank.

    As I mentioned previously in the other thread, if the above is actually how it was, then the 1971 Corvette LS-6 would be the only Corvette with Holley carburetor ever equipped with a right side fuel return line. Actually, it's my belief that this is how it was.

    Does anyone have any information from a KNOWN ORIGINAL 1971 LS-6 that would confirm it was equipped with an AC type 40770 fuel pump and a right side fuel return line? I'm not talking about a car that was originally a non-LS-6 but was converted to LS-6. I'm talking about a KNOWN ORIGINAL LS-6.
    In Appreciation of John Hinckley
  • Terry M.
    Beyond Control Poster
    • September 30, 1980
    • 15582

    #2
    Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

    Originally posted by Joe Lucia (12484)
    I'm starting a new thread on this because some recent discussion on this topic was done as part of another thread relating to LT-1 fuel lines.

    There is no information in the 1971 AIM relative to the above referenced topic components. The information that I've been able to glean from SERVICE parts info (which, by the way, originates from PRODUCTION information) is a bit vague. In any event, it would seem that 1971 LS-6 was originally equipped with an AC type 40770 fuel pump. This pump has provisions for fuel return. It would then follow that the LS-6 equipped Corvettes were also equipped with a fuel return line co-located with the fuel supply line and a fuel tank with provisions for a fuel return line on the upper right side of the tank.

    As I mentioned previously in the other thread, if the above is actually how it was, then the 1971 Corvette LS-6 would be the only Corvette with Holley carburetor ever equipped with a right side fuel return line. Actually, it's my belief that this is how it was.

    Does anyone have any information from a KNOWN ORIGINAL 1971 LS-6 that would confirm it was equipped with an AC type 40770 fuel pump and a right side fuel return line? I'm not talking about a car that was originally a non-LS-6 but was converted to LS-6. I'm talking about a KNOWN ORIGINAL LS-6.
    I would encourage researchers to look at MF Dobbins Vette Vues Fact Book for 1971 (I can't recall is it was 1968-1972 or more nuanced) but there are two full page photos of an LS6 engine compartment in that book. I am not sure if the chassis fuel lines are visible in either of those photos, but I am familiar with that car and it is now a 5-Star Bow Tie car with around 6000 miles on it last time I saw it. It hasn't moved since then either.

    So if either of those photos shows what you want, you can take it to the bank. If those photos don't help, I have some other options but it will take a while for me to accomplish them.
    Terry

    Comment

    • Joe L.
      Beyond Control Poster
      • February 1, 1988
      • 43199

      #3
      Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

      Originally posted by Terry McManmon (3966)
      I would encourage researchers to look at MF Dobbins Vette Vues Fact Book for 1971 (I can't recall is it was 1968-1972 or more nuanced) but there are two full page photos of an LS6 engine compartment in that book. I am not sure if the chassis fuel lines are visible in either of those photos, but I am familiar with that car and it is now a 5-Star Bow Tie car with around 6000 miles on it last time I saw it. It hasn't moved since then either.

      So if either of those photos shows what you want, you can take it to the bank. If those photos don't help, I have some other options but it will take a while for me to accomplish them.
      Terry------


      I have the Dobbins "Fact Book" (at least the "revised 2nd edition"). It covers 1968-1972 and does have several pages of photos of the LS-6 engine compartment. Unfortunately, none show anything regarding the fuel pump or chassis fuel lines. As a matter of fact, most of the photos in that book are horrible and lack detail.
      In Appreciation of John Hinckley

      Comment

      • Mike E.
        Extremely Frequent Poster
        • February 28, 1975
        • 5136

        #4
        Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

        I guarantee you, scouts honor, that real, true, unaltered, factory-original, unmodified, never-changed, as they were built, never-messed-with LS6 cars had the dual fuel line. Gary Bosselman, Jim Wallace, Warren Friedrich would be guys to check with regarding that. I have one near me that still has ink stamps on the carb, all original components except for differential, iron-clad 3-owner history with the MSO, with the original 40770 fuel pump dated and stamped 19K40770 (January 19, ‘71) , and it has the dual fuel line. I am in the process of doing an article for the 50th anniversary of the LS6 (March 1, 2021), and there is information in that article as to why it used the return line, and that is related to the late release (end of February) of the LS6, even though GM had the carbs, distributors, etc built already in August/September of 1970.
        Last edited by Mike E.; May 19, 2019, 04:58 PM.

        Comment

        • Ed V.
          Infrequent User
          • December 1, 1986
          • 5

          #5

          Comment

          • Terry M.
            Beyond Control Poster
            • September 30, 1980
            • 15582

            #6
            Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

            Originally posted by Joe Lucia (12484)
            Terry------


            I have the Dobbins "Fact Book" (at least the "revised 2nd edition"). It covers 1968-1972 and does have several pages of photos of the LS-6 engine compartment. Unfortunately, none show anything regarding the fuel pump or chassis fuel lines. As a matter of fact, most of the photos in that book are horrible and lack detail.
            Dobins used the same pictures of that car's engine compartment in all the editions I have seen, so if they are not in the edition you have they are not in any of them. I will look in my computer and scrapbook when I get home. The seafood is wonderful here in New England, and I expect to stay a while
            I am surprised Mike E doesn't have photos of that car. I know someone else who has some photos that may be helpful, but he is with me but allergic to sea food. Sad.

            There is a very original LS6 that currently resides in Texas that will be in the Special Collection at Bloomington Gold in June. I judged it last year at that event, and I am pretty sure it achieved a Survivor and perhaps even Benchmark Award then. It is also fairly low miles, but I don't know the history of that car prior to the current owner. I will make inquiries at the event this year and see what I can find out. In the mean time i expect Drew P has the history of that car.

            I am puzzled at all the interest in this detail since all the LS6s we have judged, regardless of which event, have presented with the fuel return line on the passenger side. Perhaps Chevrolet Engineering found fuel percolation was an issue this this engine.
            Terry

            Comment

            • Gary B.
              Very Frequent User
              • July 31, 1979
              • 926

              #7
              Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

              This is a picture from that car Terry describes.
              Gary B

              Attached Files

              Comment

              • Terry M.
                Beyond Control Poster
                • September 30, 1980
                • 15582

                #8
                Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

                Originally posted by Gary Bosselman (2575)
                This is a picture from that car Terry describes.
                Gary B

                That car is not only about 6K miles, but two owners. The current owner bought it in the late 1970s and I have known the car since the early 1980s. Take that one to the bank.

                I will pursue the one from Texas next month.
                FWIW: I would guess I have judged around a dozen or 15 LS6s over the years but the one above and the one from Texas are the most original I can remember.
                Terry

                Comment

                • Mike E.
                  Extremely Frequent Poster
                  • February 28, 1975
                  • 5136

                  #9
                  Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

                  Here is the car near me.
                  Attached Files

                  Comment

                  • Gary B.
                    Very Frequent User
                    • July 31, 1979
                    • 926

                    #10
                    Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

                    This is a 13,22 mile LS6 from Texas. The other car Terry McManmon was talking about.
                    Gary Bosselman

                    Attached Files

                    Comment

                    • Gary B.
                      Very Frequent User
                      • July 31, 1979
                      • 926

                      #11
                      Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

                      And a 70 Chevelle, LS-6 that belongs to friend of mine.
                      Gary Bosselman

                      Attached Files

                      Comment

                      • James G.
                        Very Frequent User
                        • August 22, 2018
                        • 791

                        #12
                        Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

                        I didn't even think to check the 4300 mile 70 LS6 my customer has...
                        Attached Files
                        James A Groome
                        1971 LT1 11130 - https://photos.app.goo.gl/zSoFz24JMPXw5Ffi9 - the black LT1
                        1971 LT1 21783 - 3 STAR Preservation.- https://photos.app.goo.gl/wMRDJgmyDyAwc9Nh8 - Brandshatch Green LT1
                        My first gen Camaro research http://www.camaros.org/forum/index.p...owposts;u=4337
                        Posts on Yenko boards... https://www.yenko.net/forum/search.php?searchid=826453

                        Comment

                        • Joe L.
                          Beyond Control Poster
                          • February 1, 1988
                          • 43199

                          #13
                          Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

                          Originally posted by Gary Bosselman (2575)
                          And a 70 Chevelle, LS-6 that belongs to friend of mine.
                          Gary Bosselman

                          Gary------


                          This does surprise me. GM specified that fuel pump AC type 40727 was used for 1970 Chevelle with LS-6. The 40727 does not have provisions for fuel return. It would be interesting to see what the 1970 Chevelle AIM says about this although, if it's like the Corvette AIM for RPO LS-6, it won't have any part number for the fuel pump.
                          In Appreciation of John Hinckley

                          Comment

                          • Dean N.
                            Infrequent User
                            • July 31, 1989
                            • 27

                            #14
                            Re: 1971 LS-6 Fuel Lines, Fuel Pump, and Fuel Tank

                            I have a 71 LS6, I have owned from 1992, car has always been in northern IL all of it's life, has had one repaint and normal maintenance over the years. I took the attached photo last night of the fuel lines if this helps.........

                            Dean Nelson
                            Attached Files
                            Dean Nelson
                            1967 327/300 3-speed- Bowtie - P.V. - Duntov
                            1971 454/425 LS-6
                            1990 LT5 ZR-1 bought new

                            Comment

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