1964 L76 vs. L84 - NCRS Discussion Boards

1964 L76 vs. L84

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  • Michael J.
    Extremely Frequent Poster
    • January 27, 2009
    • 7118

    1964 L76 vs. L84

    I will soon get my "new" '64 L76, and since I know nothing about that year and engine, I wanted to ask the experts what the differences are between its' L76 engine and the L84 FI engine. They are listed as being within 10 HP of each other, just wondering what the engine differences are besides the obvious intake system, thanks!
    Big Tanks In the High Mountains of New Mexico
  • William C.
    NCRS Past President
    • May 31, 1975
    • 6037

    #2
    Re: 1964 L76 vs. L84

    Virtually none except the FI vs carburetor.
    Bill Clupper #618

    Comment

    • Mike E.
      Very Frequent User
      • June 24, 2012
      • 920

      #3
      Re: 1964 L76 vs. L84

      A few years ago Vette Magazine asked the same question. Well kind of.



      Mike

      Comment

      • Michael J.
        Extremely Frequent Poster
        • January 27, 2009
        • 7118

        #4
        Re: 1964 L76 vs. L84

        Thanks guys, just what I needed. Mike, that article is great, too bad it wasn't exactly the same as the old school engines, but close I guess. Interesting about the cam swap with the Duntov cam, I wouldn't have thought it would have improved it that much over Duntov's engineering, but modern technology.....
        Big Tanks In the High Mountains of New Mexico

        Comment

        • Duke W.
          Beyond Control Poster
          • January 1, 1993
          • 15661

          #5
          Re: 1964 L76 vs. L84

          The FI manifold is much more efficient than the SHP manifold, but head flow is the major restriction so FI only makes 2-3 percent more top end power with Flint-machined heads. A good head massage will double the advantage.

          BTW, the camshaft referal as a "Duntov 30-30" is a misnomer. The only "Duntov" cam is the '56-'63 OE mechanical lifter cam. The 30-30 was not personally designed by Duntov like the ...097, but I'm sure he had some input.

          The other thing to remember is that the performance curves will be significantly different with manifolds compared to the large tube headers they used. Torque and power will be down through most of the range except for the bottom end, which, of course, they didn't test.

          Headers make good use of wave dynamics to scavenge the cylinder during the overlap period and relatively high overlap is good. Manifolds don't like overlap, and the less the better for any given duration.

          Duke

          Comment

          • Michael J.
            Extremely Frequent Poster
            • January 27, 2009
            • 7118

            #6
            Re: 1964 L76 vs. L84

            Thanks Duke, I guess that same head message would also help the L76? Just not as much as the L84?
            Big Tanks In the High Mountains of New Mexico

            Comment

            • Dick W.
              Former NCRS Director Region IV
              • June 30, 1985
              • 10483

              #7
              Re: 1964 L76 vs. L84

              Plus you do not have all the inherent maintenance issues with a carburetor that you do with fuel infestation
              Dick Whittington

              Comment

              • Dan H.
                Extremely Frequent Poster
                • July 31, 1977
                • 1369

                #8
                Re: 1964 L76 vs. L84

                FIs aren't that hard to maintain, they offer equal fuel/air to each cylinder, WAY better than any carb set up. The parts are very available and some are an improvement on Rochesters parts. Have had both setups, really like the FI for all around driving etc. Run my 64 on pump gas, maybe a little Marvel Mystery oil just for the snake oil lovers!
                1964 Red FI Coupe, DUNTOV '09
                Drove the 64 over 5000 miles to three Regionals and the San Jose National, one dust storm and 40 lbs of bugs!

                Comment

                • Duke W.
                  Beyond Control Poster
                  • January 1, 1993
                  • 15661

                  #9
                  Re: 1964 L76 vs. L84

                  Originally posted by Michael Johnson (49879)
                  Thanks Duke, I guess that same head message would also help the L76? Just not as much as the L84?
                  Yes, but once you massage the heads on a L76 the inlet manifold is the next biggest restriction, which is why FI pulls further ahead. The LT1 manifold in place of the 327 SHP manifold will make up most of the distance.

                  Duke

                  Comment

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