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EFI Conversion for Chevy 350

boarditupboarditup Posts: 585 Crazy Baller
A buddy put me onto this - Howell EFI builds a conversion kit for older Chevy small blocks from carb to EFI. They build marine grade kits and claim to have converted over 1,000 boats. The harnesses are built for each application, but they use mostly GM parts. If you have an older boat and want the EFI, and have about $1,500 it is an option. It is not drive by wire, so ZO is not an option. However, PP is an option since it uses stock GM linkage.
Karl DeLooff - Powered by the wind


  • RichardDoaneRichardDoane Posts: 4,151 Mega Baller
    BallOfSpray Pacific Northwest Vice President of Event Management, aka "Zappy"
  • RichardDoaneRichardDoane Posts: 4,151 Mega Baller
    just remember to use a USCG approved flame arrestor and fuel lines, but how well will it work without an oxygen sensor ?, I'd just fix the old carb and go ski with the $1000 I didn't spend
    BallOfSpray Pacific Northwest Vice President of Event Management, aka "Zappy"
  • JoepruncJoeprunc Posts: 262 Baller
    $1350 = a lot of boat gas.
  • boarditupboarditup Posts: 585 Crazy Baller
    They have a marinized kit available - it adds about $100. Their kits have been used on USCG inspected passenger vessels. They have an O2 kit for the mainfold.

    Yes, it is a lot of gas, but it may be worth it to someone. I really like the drivability of EFI. I had a carb boat and spend a lot of time on it. Three rebuilds over a decade due to alcohol in fuel and dirty gas. Each time it was a pain to get it adjusted right.
    Karl DeLooff - Powered by the wind
  • kmenardkmenard Posts: 158 Baller
    So instead of rebuilding the carb, you are doing the injectors.

    Holley has one:
    I think MSD has one too.

    Remember the early 90's truck with throttle body injection? Remember how much they sucked? It really isn't worth it.
  • gregygregy Posts: 2,583 Mega Baller
    I've used the Howell kits on several auto projects with good success. The throttle bodies are a very simple system. Howell really stands by there product as well. I've had to call them multiple times for help and they always answered the phone or called me back quickly.

    I've worked on the vehicles with the Holley kits and never could get them to run right.

    Throttle body injection was used on some boats in the 90's. I regularly ski behind a PS205 Mastercraft that has a 350ci gm with throttle body and PP stargazer. It skies great.
  • WishWish Posts: 7,848 ★★★Triple Panda Award Recipient ★★★
    I ski behind 2 different Malibu Echelons from the 90s when in MN with throttle bodies. Both boats work very well. One very well mechanically maintained and the other not so much. No difference that I can tell. Not sure that would be the case if they were both carbed.
    >>> 11.25..a different kettle of fish. <<<
  • 454SS454SS Posts: 169 Baller
    makes starts a lot easier and more reliable
  • swc5150swc5150 Posts: 2,259 ★★★Triple Panda Award Recipient ★★★
    Do you mean rebuild the carb or repair/replace injectors, pick your poison? Just curious, as we've never experienced a single issue with any of our numerous EFI boats. All but 1 of our carbed boats needed carb work.
    Scott Calderwood
  • kmenardkmenard Posts: 158 Baller
    Yes, the corrosives that will enter the carb, are going to enter a fuel injection system as well. Before storage every year I make sure to run the last tank with Sta-bil and I have never had a problem...granted, I also run a Holley and not a quadrajet, but FI or Carb if you let stake fuel sit over the winter, you will have issues with everything from rubber lines to needle and seats, etc. Often it is the stuff downstream from the carb that is getting old and corroded that is causing the problems upstream.
  • BraceMakerBraceMaker Posts: 3,790 Mega Baller
    I had to do o-rings on tge transfer tubes of my carb this year. First carb work of the last 5 years. Debating rebuild next winter
  • Jody_SealJody_Seal Posts: 2,751 Mega Baller
    The biggest problem I see with aftermarket throttle body injection is that if the mapping is off the front and rear cylinders have the potential to run lean and could cause catastrophic failure. Keep in mind all the Indmars running to this day with throttle body injection (and it is still available) run for the most part fine, however their mapping is fat fat fat!!!
    Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.

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