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I've Had It With My Holley 390, Whats Next.

Discussion in 'Early CJ5 and CJ6 Tech' started by windyhill, Sep 21, 2016.

  1. Sep 21, 2016
    windyhill

    windyhill Sponsor

    PA
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    For years I've struggled with my Holley 390 carb. From new it's always had a hiccup / hesitation when I step on it. I've had diff carb shops look at it, and work on it. etc. never been right. Now when I look down the throat one of the round parts that hangs out in the opening is part melted off. It still runs, I'm just ready for something new. So looking for suggestions.
    I'm running a .030 over 225 with a mild comp cam, HEI dist. and Offenhauser Intake. I'd like to stick with my intake and am looking for good reliable setup that also performs off road on occasion.
     
  2. Sep 21, 2016
    RATTYFLATTY

    RATTYFLATTY I think you need a little more throttle

    Central MN
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    I know it's not first on the list for some but I run a Motorcraft/Autolite 2150. I have it mounted on my 225 which has An Offy 360 Dual Port, HEI, and stock manifolds. I have no idea on the cam as it was a used motor that was rebuilt when I got it. It works great offroad, it's simple, easy to tune and delivers 14-17 mpg.
     
  3. Sep 21, 2016
    colojeepguy

    colojeepguy Colorado Springs

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    If the venturi booster melted, you must have had a carb fire or one hell of a backfire!

    I'm running a Holley TA470 on mine, but it took quite a bit of tuning to get it running right.
     
  4. Sep 21, 2016
    windyhill

    windyhill Sponsor

    PA
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    Ya the melted venturi is just the latest issue.
     
  5. Sep 21, 2016
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Did the 390, went to the TA470 for a while, now with the EZ-EFI on both my rigs. I will be helping a neighbor do his EFI on his 225 this winter (so he says). I'll be validating if the two new items could be a cheaper/better setup - it all depends on if they can take the Tach from the HEI like the EZ-EFI.

    https://www.summitracing.com/parts/fif-30003/overview/
    https://www.summitracing.com/parts/fif-40003/overview/

    I dropped the EZ-EFI on the '51 and didn't have any time to let it 'learn' before heading up for camping. Other than a couple hard starts first thing in the morning (it was below 40) it ran flawlessly while there for a week going from @ 9K to over 13K. While a bit more coin, I'll never go back to a carb.
     
  6. Sep 21, 2016
    Vanguard

    Vanguard Take Off! Staff Member

    Vista, CA USA
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  7. Sep 21, 2016
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    It'll require an adapter for a 4 bbl intake...
     
  8. Sep 21, 2016
    wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
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    My Holley 2 bbl has a dead spot right off idle that I can't get rid of. Other than that, I like it a lot. Even with the dead spot, I like it better than the 2g.

    That being said, if you have the coin, go EFI as Chuck suggests. Then I can copy your work after seeing it first hand.:whistle:
     
  9. Sep 21, 2016
    Chilly

    Chilly Active Member

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    I dont have a lot of experiences with different options but my Motorcraft 2100 causes me to not look for alternative solutions. Starts pretty easy, no stumbles, takes full throttle without hesitation. That is after a full rebuild, including power valve. I'm in PA so dont climb mountains or take to brink of roll-over.

    I was considering "upgrade" carb options a while back but after some web research concluded that the MC2100 was near perfect for carb options. Mine runs fine and I've determined I have no reason to change.
     
  10. Sep 21, 2016
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
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    I know you want to stick with your Offy manifold, but I still give VERY high marks to the stock Rochester 2 bbl carb. I've had my 71 for 10 years and the only complaint I'll register is very rough hill climbs.
    I just put a new engine in my '71 and added HEI. I've run the new engine for almost 500 miles. I've had it to 13,000' with no problems. It runs great!
    I'm almost ready to get this NEW carb just to make the entire engine new, but I'm hesitating since I have no complaints with the original carb.
    https://www.summitracing.com/parts/urm-16-1632
    I've read everybody's report here with aftermarket carbs, both 2 bbl & 4 bbl. I'm here to say I'll stick with the stock 2CG. (y)
    Fuel Injection is NOT in my EarlyCJ5 future.
     
    Last edited: Sep 21, 2016
    fhoehle likes this.
  11. Sep 21, 2016
    Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Maryland
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    Flame suit on. Quadrajet
     
    73 cj5 likes this.
  12. Sep 21, 2016
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Qjets are great - just hard to find most of the time (at least here they are). The I believe the Offy intake has the holes for a spread bore too.
     
  13. Sep 22, 2016
    tarry99

    tarry99 Member

    Northern California
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    Sorry to hear your having issues with the little Holley 390 carb...........for the most part any carburetor you stick on the Odd Fired motor is going to require some tuning..........nature of the beast with the firing order. The good news with the Holley lineup is there are plenty of parts out there to tweek it some.......power valves , accelerator pump volume sizes and ramps. Even the vacuum operated secondary's can be tuned to open a little earlier.

    Off road the little 390 was always a challenge but with available parts now that is no longer an issue.

    Have you tried advancing the timing a few degrees to see if that takes the dead spot out?
     
  14. Sep 22, 2016
    Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Maryland
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    They vary I've seen square bore intakes. My Offy 360 dual plane is setup to take a spread bore
     
  15. Sep 22, 2016
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    I've run the old Rochester 4-jet (pre-quadrajet) 4 bbl from the Buick 215 V8 with good success on the 225 odd-fire. They are getting hard to find, and make sure you get one with the aluminum base, otherwise, the iron base ones are likely from the late '50s Chevys. They are real picky about float levels, but once you dial that in, they work real well.
    -Donny
     
  16. Sep 22, 2016
    windyhill

    windyhill Sponsor

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    How much total cost to switch to EFI? can I use my stock fuel tank?
     
  17. Sep 22, 2016
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I used the more expensive EZ-EFI setup than those listed. I have not put one of those on, but don't think there would be an issue. My first item would be to call FITech and verify it can take a tach signal from an Odd Fire HEI (should, all those that work with HEI like the EZ-EFI work), just to be sure. IF you use the commander module, you can use your current tank and plumb the current mechanical fuel pump to the commander. The commander runs the high pressure system to the throttle body and back so your needs for high pressure lines and such are limited.

    The kits are supposed to come complete with everything you need at @ $1200, I like to figure for 'dang' and our current estimate is $1500 or less to put that on my neighbors jeep. Read some reviews - it's rated better than what I'm using now :)
     
  18. Sep 23, 2016
    windyhill

    windyhill Sponsor

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    EFI is sure getting more tempting. Thanks all for the responses. Sounds like there really isn't a good out of the box carb out there. I want it to run when I need it, not fall on its face.
     
  19. Sep 24, 2016
    fhoehle

    fhoehle Sponsor

    Harford Township, PA
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    I have had 390 Holleys, and a 470TA that took a lot of tuning to get right. I have a stock 225, and for me, the best driveability and usefulness came from putting a rebuilt 2G on. My mileage improved, and it has more guts down low. If I didn't do the 2g, I'd probably talk to Warloch about injection. I run some hard trails, at some pretty bad angles, and no issues. I tow a camper, trailer and drive to work. My needs have to be from an 'all around' perspective. The 2G does give up some oomph at the high end though, but I'm not a race car type guy, so (shrugs) oh well. Good luck in your search.
     
    dnb71R2 likes this.
  20. Sep 24, 2016
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Northern California
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    I am very happy with my MC 2100 with 1.08 venturi. I ordered mine from this ebay seller. ehrmannmp on eBay
    The carb came ready to bolt on with adapter. Fired right up and I have made no adjustments other than idle speed. I have checked the plugs a couple times and the jetting looks to be perfect. I live at 500' elevation and have run it up to 7500' with zero adjustments needed.
    My wife drives my jeep to work (40 mi round trip) atleast 3 days a week. Needless to say I cannot have carburetor issues or quirks going on when I'm not around.
     
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