Definition - Big Block vs Small Block - NCRS Discussion Boards

Definition - Big Block vs Small Block

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  • Joe L.
    Beyond Control Poster
    • February 1, 1988
    • 43203

    #31
    Re: It's real simple...

    Duke and Verne-----

    Yes, the Mark I big block engine ("W"-series) was first installed in BOTH passenger cars and trucks for the 1958 model year. It saw its final use for 1965. So, it was a quite "short-lived" engine design as engines go. GM must have lost money on that one. It's hard to imagine that the cost of design, development and tooling could have been amortized over such a short period with a relatively small number of engines produced.

    As far as "big block" engines are concerned for Chevrolet, they have always pretty much relied on the "dual use" type of application (i.e. cars and trucks) to make them economically feasible. This was also true of the Mark IV. If there hadn't been BOTH car and truck applications planned at the time, I doubt that the engine would have "seen the light of day". It required the volume generated by both applications to cover the costs. Don't forget, the Mark IV was never widely used in passenger cars and I don't think that GM ever thought it would be. However, considering the passenger cars sales and the truck requirements, I suppose that a business case could be made for developing the engine.

    After the passenger car applications for the Mark IV ended for good in 1975 and the truck installations greatly diminished, the big block engine languished. It was revised in 1992 for the so-called Mark V, again in 1996 for the so-called Mark or Gen VI, and once again in 2002 for the 8.1L. However, all of these engines are based on the Mark IV. They are really not new designs, at all. The volume of engines sold in this size range just would not be sufficient to justify developing a completely new engine. I think the "progeny" of the Mark IV will likely live on, perhaps throughout our lifetime, because there's just no viable way to replace it. In fact, it still stacks up very well against whatever the competition can throw at it.

    In this day and age, even the development of the Gen III small block depended on use across both car and truck lines, with much more heavy emphasis on truck than at any time in the past (even the Mark I big block development). With so little V-8 engine application in passenger cars, there's no way the Gen III small block would have "seen the light of day" without the truck application and requirement and the need to have a competitive engine there. Were it not for trucks, I feel very sure that the Corvette would still be running the Gen I or II small block to this very day, regardless of the fact that Corvette was first to use the Gen III. The Gen III engine was NOT developed for Corvettes; it was developed for trucks and given to Corvette as a "launch platform".
    In Appreciation of John Hinckley

    Comment

    • mike cobine

      #32
      This is a Big Block

      You can tell by the big heads and the funny angles of the valves.




      Comment

      • mike cobine

        #33
        And This is a Small Block

        Smaller head, shorter block.

        The questions you need, do you want relatively cheap horsepower and tons of torque or one that revs so high, it will scare you.

        If you notice, the fuel pump mount is different and readily noticable. Head exhaust port configuration is different and also readily distinguishable.




        Attached Files

        Comment

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

          #34
          Re: And This is a Small Block

          And here's a really BIG big-block




          Attached Files

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

            #35
            Re: It's real simple...

            And nailhead Buicks fit VERY nicely in '53 Corvettes (in 1959)
            Attached Files

            Comment

            • Roy B.
              Expired
              • February 1, 1975
              • 7044

              #36
              Re: It's real simple... John

              John
              Was that your 53 Corvette, I just cant help my self but if you look closely at the top welt it has the original S/S end cap that they say is wrong to day which I also have on my 55 and every Corvette I saw back in the early 60's, there is a left and right and I also saw many Buick and Olds engines in them also.




              Comment

              • Verle R.
                Extremely Frequent Poster
                • March 1, 1989
                • 1163

                #37
                Re: Definition - Big Block vs Small Block

                Mark,

                The LT5 is not a "small block" chevy engine. It is an independant design by Lotus Engineering in the UK. I don't know of any parts that are interchangable with small block Chevy engines. In physical size the LT5 is about the same length as the small block and is wider than the big block. It is all aluminum and weights about 800 lbs. So it is NOT a SMALL engine.

                Verle

                Comment

                • mike cobine

                  #38
                  Re: And This is a Small Block

                  A friend of mine had one of those in an old Hudson. At least, it seemed that long.

                  Comment

                  • Verle R.
                    Extremely Frequent Poster
                    • March 1, 1989
                    • 1163

                    #39
                    Re: It's real simple...

                    Were GMC truck engines ever offered in larger Chevrolet trucks? I know some of them were large dispacements back then.

                    Verle

                    Comment

                    • mike cobine

                      #40
                      Re: Definition - Big Block vs Small Block

                      I have half of a LT5 sitting in a garage. It is called a 907.




                      Attached Files

                      Comment

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

                        #41
                        Re: It's real simple... John

                        Roy -

                        As far as I know, that's the original top - I bought the car off a used-car lot in Columbus, Ohio in 1959 for $900, painted it black, converted it to 12V, sold the engine/trans to a buddy for his Dad's pickup, and put the '57 Buick and a LaSalle 3-speed trans and 4.56 axle in it. Had a 3x2 intake on it in the photos, later replaced by a 6-71 blower and a pair of WCFB's. It was my "Woodward car", and ran 12.20's @ 121 in AM/SP at the '61 NHRA Nationals at Detroit Dragway (lost in the semi-finals to a little Italian Bandini with a blown Caddy in it). Remember Harman-Collins roller cams?

                        Comment

                        • Roy B.
                          Expired
                          • February 1, 1975
                          • 7044

                          #42
                          Re: It's real simple... John

                          Just one of the original little things few care about. OH well!! how is sacc going? your the teck-guy then you drive your Corvette too.

                          Comment

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