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350 Chevy fuel usage?

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  • 350 Chevy fuel usage?

    Hi all, I have a question or 2 on fuel useage, I recently finished rebuilding a 25' Wellcraft Airslot, I love the boat in every way, but I need to get it to use less fuel. At current I am using 10+GPH running at around 3200RPM, which is around 18knots. I have a Volvo Penta 280(350 Chev v8) and I have the following options that I can try;-Leave it stock with the 4BBl thats on it-I have a Holley Projection marine unit that is a 2bbl TBI system, I think it would be nice but to many things to go wrong on a boat.-I have access to a 2BBl manifold and carbOut of these three options I like the idea of going to a 2bbl and running it like that for simplicity(I am 45 miles offshore alot) but I am not sure what this will do to the overall performance of the boat, I am looking to maximise my fuel efficiancy and still be able to run around 20knots!So any of you have any ideas which I should try?Also I notinced the other day that I have a Stock GM HEI distributor in the boat, and where the computer is supposed to hook up(There is no computer) there is a jumper that forces teh distributor to run at base timing which is 10 degrees, will I get better fuel effeciancy by installing a distributor that advances to 28degrees like its supposed to?Thanks for your time!John

  • #2
    Re: 350 Chevy fuel usage?

    It,s pretty easy really just slow down. I have the same engine and burn 3 gallons an hour. Just leave a little earlier Your going way to fast to get good fuel consumption


    • #3
      Re: 350 Chevy fuel usage?

      If cost is not an issue I would go with the Holly Progection. How many problems do you have with the electronic fuel injection on your car. The Projection is not as complicated as a car. Easier starting, smoother runing,less fuel.Also if you are only getting 10 degrees of advance that needs to be addressed first. You need an eariler model non-computer centrifical advance HEI distributor with 32 degrees total advance. This will help economy. Sounds like the previous owner put in the wrong distributor.Buttanic


      • #4
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        Re: 350 Chevy fuel usage?

        Recordhunter I have no problem with slowing down for the most part, but I still suck 7 gallons an hour at 2500rpm, there is more wrong here. Buttanic I already have the Holley projection installed and for the most part I like it, but it has this problem I have to do a clear flood everytime I start it and I am not able after 3 weeks of attempting everything there tech support suggest to get rid of it. I am on the distributor that will be changed tomorrow and I will start over from there.Thanks for the replies guys!