3758932 intake atypical for 4900R Fuel Injection Unit in 1959? - NCRS Discussion Boards

3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

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  • Ian G.
    Extremely Frequent Poster
    • September 3, 2007
    • 1114

    3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

    My aluminum winters intake for my 7014900R Fuel Injection Unit is 3758932. I assume this is atypical for judging since the guide says it should be 3748947. However, My 1959 GM parts manual lists 3748947 for 57-58 and then 3758932 for 59, and it was used for all other Fuel Injection combinations in 1959. Given the parts guide I'm wondering if there's a chance this is still a possible "original" combination for 59. I've got is a December 58 car.

    I know the combination is not original to the car though. The last owner bought this and included in a box. The car had a carb on it, as is common with old Fuelie cars that have not been restored. Anyone ever seen this combination? How many points will I lose if I leave it as-is? I imagine with the port gasket installed you can't see the number either.

    What functional difference? the top looks basically the same, but I notice the bottom distributor hole surface and oil filler hole bottom surface are open on the inward side on the 3748947 but closed on the 3758932.... With the oil filler bottom open like that, I guess more fumes escape? Not a big deal, aside from smog With the distributor hole closed would the distributor get enough oil on the gear?





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    Last edited by Ian G.; November 4, 2017, 04:50 PM.
  • Dennis C.
    Very Frequent User
    • June 30, 2002
    • 884

    #2
    Re: 3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

    Ian,

    Best advice I can give you is to reach out to Tim Mickey, the Team Leader.

    Dennis

    Comment

    • Ian G.
      Extremely Frequent Poster
      • September 3, 2007
      • 1114

      #3
      Re: 3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

      Thanks Denis, Looking at it externally I don't think a judge could tell that it is any different. The difference seems to be the distributor hole base and oil filler hole base. It seems to me they are there to prevent blow by emissions from the block valley at those locations? I wonder if this was an early "voluntary" smog prevention step before they did the PCV valve in 61 and eliminated the draft tube? The PCV wouldn't have been required till 63 either. The clean air act came in 63, but California setup its smog board in 59, and there was a federal advisory law in 55.

      Comment

      • Dennis C.
        Very Frequent User
        • June 30, 2002
        • 884

        #4
        Re: 3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

        Don't underestimate what a judge will notice on the judging field.

        Case in point -

        About two years ago I was at an event judging 61 - 62 mechanical. We had four cars to judge and all of them appeared to have original 091 coils. This struck me odd and on the last car my mirror wound up checking the bottom of the coil. I discovered that when the owner was freshening up some paint, he painted the coil, but never painted the bottom of the coil. The bottom of the can was bare steel.

        While I didn't take a deduction (not enough points on the line item given 80+% of the coil was correctly painted), I did make a note of it. I don't think I had ever looked at the bottom of a coil before when judging.

        As a judge, I always feel better when an owner is prepared for potential deductions. I don't find it pleasant to have to break bad news to an owner. Judging mechanical, it happens more times than I like.

        Regards,

        Dennis

        Comment

        • Ian G.
          Extremely Frequent Poster
          • September 3, 2007
          • 1114

          #5
          Re: 3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

          Thanks Dennis. Strange! I guess that owner is wishing he'd painted the bottom of that coil If I lose points in the end, it will be my fault, not the judge I know you guys are just there to help. I'm most interested in what the functional difference could be to these two intakes based on the differences in the distributor and oil filler holes?

          Comment

          • Joe L.
            Beyond Control Poster
            • February 1, 1988
            • 43220

            #6
            Re: 3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

            Originally posted by Ian Gaston (47813)
            My aluminum winters intake for my 7014900R Fuel Injection Unit is 3758932. I assume this is atypical for judging since the guide says it should be 3748947. However, My 1959 GM parts manual lists 3748947 for 57-58 and then 3758932 for 59, and it was used for all other Fuel Injection combinations in 1959. Given the parts guide I'm wondering if there's a chance this is still a possible "original" combination for 59. I've got is a December 58 car.

            I know the combination is not original to the car though. The last owner bought this and included in a box. The car had a carb on it, as is common with old Fuelie cars that have not been restored. Anyone ever seen this combination? How many points will I lose if I leave it as-is? I imagine with the port gasket installed you can't see the number either.

            What functional difference? the top looks basically the same, but I notice the bottom distributor hole surface and oil filler hole bottom surface are open on the inward side on the 3748947 but closed on the 3758932.... With the oil filler bottom open like that, I guess more fumes escape? Not a big deal, aside from smog With the distributor hole closed would the distributor get enough oil on the gear?





            Ian-----

            I don't think there is any functional difference between these FI adapters (manifolds) which would preclude them from being used interchangeably. In fact, it's even possible that one may have replaced the other for SERVICE at some later time. I can't check on that right now, though, since I'm out of town.
            In Appreciation of John Hinckley

            Comment

            • Ian G.
              Extremely Frequent Poster
              • September 3, 2007
              • 1114

              #7
              Re: 3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

              That definitely seems to be the case looking at my 59 parts book. I'm guessing the Fuel injection unit was delivered as an assembly including the intake from Rochester? The 7014900 & 900R were the only ones using the older intake in the 59 lineup (the 200,250,300 & 300R used the 3758932 or 3768233) and the 7014900R were just recalibrated leftover 1958 7014900 units.

              Comment

              • John D.
                Extremely Frequent Poster
                • December 1, 1979
                • 5507

                #8
                Re: 3758932 intake atypical for 4900R Fuel Injection Unit in 1959?

                Ian, Nice photos you took. Strange place for a weld on the '947 baseplate. I will attempt to answer all of your questions except your last couple of sentences as I don't understand it.

                It would not be typical for your 7014900R unit to come from Flint, MI and St. Louis with a '932 baseplate.
                What month is your car. You told me but I forgot.
                The '932 is very late '59. I would expect to see it on a late 7017300 or for sure on a 7017250 but NEVER on a '7014900R.
                There were two versions of the '932 baseplate. The first one had the casting number partially ground off and the last three numbers stamped in by hand. Have proof.
                The second version is like the one in your photos.
                '932 is used in late '59 and early '60. It's a transition baseplate (intake). The only diffence between the '947 and the '932 is the distributor spacer.

                Judges can't see the number because of the 1/8" thick one piece baseplate gasket. So guys say go ahead and use a '932 or the later '233 on a '4900 unit. But the individuals saying this are incorrect as the tip off is the distributor spacer.

                FYI: I love to learn new info about fuel injections after 50 plus long years. Her is a good one for you friends that Don Baker taught me two weeks ago.
                I asked him why did RP and Chevy use the distributor spacer at all??? Why didn't they make the baseplate just like they do a carburetor engine and the early FI units?
                Answer: Purpose of the distributor spacer is so that when you remove the distributor you can tilt it forward to clear the firewall!!!!
                Don't you just love it?? John D

                Comment

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