Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: 345 Four Carburetor

  1. #1
    Join Date
    Oct 2009
    Location
    Mont Belvieu Texas
    Posts
    53

    Wink 345 Four Carburetor

    I finally purchased a good 4 barrel intake for my 1978 Scout II. It is a spread bore. I was planning on adapting a square bore carb. to it. What CFM should I buy? I found a deal on a new Edelbrock 600 cfm but I wasn’t sure that this is big enough. The hole reason for putting this on is power not fuel economy.

  2. #2
    Join Date
    Mar 2009
    Location
    Las Vegas
    Posts
    208

    Default

    You can run with either the 600 or 650 CFM.
    Both will be plenty for your 345 unless you've really built it big.
    '71 Basterd Scout 2
    with a 258 from a '73 CJ5
    Intake manifold with NHRA markings....go figure

    "Its (scout) four-wheel-drive capabilities are equal to anything this side of full tracks"

    David H. Petraeus for President 2012

  3. #3
    Join Date
    Oct 2009
    Location
    Mont Belvieu Texas
    Posts
    53

    Default

    It has been rebuilt but the motor is pretty much stock. I just wasn't happy with the performance of the 2 barrel.

  4. #4
    Join Date
    Mar 2009
    Location
    Las Vegas
    Posts
    208

    Default

    Go with the 600 or 650 then, you'll be much happier with the increased preformance.
    '71 Basterd Scout 2
    with a 258 from a '73 CJ5
    Intake manifold with NHRA markings....go figure

    "Its (scout) four-wheel-drive capabilities are equal to anything this side of full tracks"

    David H. Petraeus for President 2012

  5. #5
    Join Date
    Oct 2009
    Location
    Mont Belvieu Texas
    Posts
    53

    Default

    Sounds good. Thank you for the information.

  6. #6
    Join Date
    Jul 2009
    Location
    Powell, Wyoming
    Posts
    12

    Default

    If it's a spreadbore intake, you really should take a look at putting a QuadraJet on there. They're not the best for all out street performance, but they are hard to beat if you do any type of off roading at all.

  7. #7
    Join Date
    Apr 2010
    Location
    cody,wy
    Posts
    2

    Default to jax

    I just bought a 79 scout ii. I see that you live in powell, wy. I am trying to find info on a q-jet convertion. please help? I am new to the ih world. O curently have a t-quad that is junk, warped bad, on a 345.

  8. #8
    Join Date
    Feb 2009
    Location
    Aiken, SC
    Posts
    2,423

    Default

    At top rpm, the 345 can't use more than about 350 cfm. You can use a 600 or a 650, but you will be tuning it down. Continuous duty red line on a 345 is 3800 rpm.

    These engines are pigs. They were designed for school busses and dump trucks. You will get the most power out of the engine if you tune it for economy, and you will get the most throttle response with the lowest cfm carb you can find.

    Holley makes a 390 cfm carb that is excellent for an SV series engine, but the Edelbrock 1400 series works pretty well. I have used them on 2 barrel and 4 barrel manifolds, on 304, 345, and 392 engines. I took one off of a 304 on a 68 travelall and put it on a 73 travelall with 392. Ran like a champ, was already tuned perfectly. Just had to play with the linkage so that the throttle plates moved less per millimeter of pedal travel.

    The thing that gives these engines life is to advance the timing a little, but not enough to ping under load, and to open up the exhaust ports/pipes. The head design is set up so that there is a lot of velocity at low rpm for use in a dump truck or grain truck or whatever. This needs to be overcome.

    If you build up a 345 with every technique known to man, add nitrous, you will still not be able to catch a mildly modified small block in a quarter mile. The 345 outweighs a chevy 350 by about 200 lbs. Just aint gonna happen.
    Allan E.
    Curmudgeon Extraordinaire
    Charter Member, Old Hippie IH Club
    Old fashioned binder freak

  9. #9
    Join Date
    Dec 2009
    Location
    Page AZ
    Posts
    159

    Default

    I agree with Allen but I like the Holly "Economaster" carb, they are kind of like a quadrajet but seem to run better for me. I get them off ebay for $40 to $100 depending on condition. Also they are a square bore so use an adapter for some applications.
    73 1210 4x4 Travelette 5 spd. 392
    300 utility tractor
    64 Scout 80-152/ weber 32/36
    80 PARTS for 2 scouts
    73 Scout2, 304.4 spd. runs almost rust free!
    Member, Sonora Desert Scouts

  10. #10

    Default Edlebrock 1404 500cfm

    I just put an Edlebrock 1404 performer 500 cfm w/ manual choke on my 345 spreadbore. Got it off eBay for $150. EB makes a squarebore to spreadbore adapter that I picked up for $20 at Napa (on the impulse stand no less) and slapped it all together a couple of weeks ago. Still working on getting the linkage hooked up (not because of problems, just lack of free time). It sure looks nice sitting up there tho

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •