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308 carb overhaul

Discussion in 'Technical Q&A' started by chrismorse, Dec 8, 2004.

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  1. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,150
    way north california
    Full Name:
    chris morse
    #1 chrismorse, Dec 8, 2004
    The car is chronically rich, so much so that the selling dealer had to install two cats in place of my flowmaster, (el cheapo) exhaust) to get it smogged.

    The unknown and potentially prohibitive cost of smogging a 77 gtb is the reason that i bought it from a california dealer.

    So here i am with a stinky, but nice 308 that I am really attached to, and wanting to get it to run like it "should". A beautiful, Quintesential car. I am really into what a car is.
    We all make compromises: purchase price, performance, maintenance costs, luggage space, leg room and on and on and on. But I am an old guy with an old car that wants to get totally into it. I want to dump the hastilly thought out smog ****, tighten up the suspension, do light wheels, better brakes and tires and kind of optimize the package. When the $$$ is there, i would like to do hot cams, bigger venturis and maybe track wheels and slicks to really let it all out.

    I have absolutely NO conficence in the selling dealer to make the car run like it should, and NEED to do it right.

    So here I am a 56 year old fat guy looking at a carb overhaul.

    Here are the basic facts:

    Stock 308 with 24K on the clock Flowmaster exhaust , (low restreiction low cost thermal reactor replacement), rejetted carbs, and stock everyting else, (except ignition which is being upgraded to Crane xr700, better coils and iridium lugs)

    So, my question: is stock float height the way to go???

    What else do you hot rod guys suggest - I'm putting it to ya.

    With a lotta respect,
    chris
     
  2. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
    Chicago
    Full Name:
    Philip
    #2 pma1010, Dec 8, 2004
    Mike at Pierce set his 78 (or 79) up with 52 idles. No smog pumps. Passed the emissions test.
    It should idle fine with the stock float height. It should pull fine with the stock float height.
    Raising the float will richen the mixture. Lowering lean it out.

    My first step in your shoes? Check your jets and e-tubes to spec. Then, set the float heights. Then sync. THen mixture. It is not rocket science. Just be patient and careful.

    BTW, I run my P6 cam'd 308 with 52 idles. Yes 52. When I had a local dealer set it up they used 70s. A long road and lots of e-tubes later it runs like it should. Crisp throttle. Brisk acceleration. OK idle.
    All part of the "adventure" of a carb'd car.

    Philip
     
  3. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    #3 snj5, Dec 8, 2004
    Here is a chart of stock 308 Weber DCNF jetting if you do not have one.
    Would proceed as Philip has suggested. It's good to baseline the car before deciding to do anything.

    Once you get the carbs optimized for the current cams/exhaust in setting a baseline, there are many ways to go for power. You just have to decide - to blow or not to blow. LOTS of threads here for both paths. Something handy if you want is an A/F meter like an LM-1. It comes in handy for re-jetting without a dyno as you make performance tweaks.
    best
    Russ
    "Andiamo Lesti Fumando Assai"
     
  4. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,367
    NY
    #4 Steve King, Dec 9, 2004
    Chris I have 77 "no cat" car with Ansa and pertronix ign. Idles a little rich but not a problem. Runs super up to 7800 . The PO took off the air pumps but in NY they don't test these aged cars for smog. I have stock factory carb set up with jets and e tubes as well as float height. Timing is 10DBTDC . Real fun car. Enjoy PS I'm older then you
     
  5. Napolis

    Napolis Three Time F1 World Champ
    Honorary Owner

    Oct 23, 2002
    32,118
    Full Name:
    Jim Glickenhaus
    #5 Napolis, Dec 9, 2004
    Webbers once set up properly will run fine for years. In Calif. do you have to meet smog requirements for model year indef?
     
  6. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,150
    way north california
    Full Name:
    chris morse
    #6 chrismorse, Dec 9, 2004
    Thanks for the advice gents. Here in Humboldt county, we do not have biannual smog tests. A cirt is only required on resale. Unfortunately the legislature just dropped the 30 year exemption.

    After looking at recent posts, i am definitely pulling the air injection trash and stuffing it in a box for later misuse.

    Onward through the fog,
    chris
     
  7. Napolis

    Napolis Three Time F1 World Champ
    Honorary Owner

    Oct 23, 2002
    32,118
    Full Name:
    Jim Glickenhaus
    #7 Napolis, Dec 9, 2004
    Sounds like a plan!
     
  8. BigTex

    BigTex Seven Time F1 World Champ
    Owner Rossa Subscribed

    Dec 6, 2002
    79,386
    Houston, Texas
    Full Name:
    Bubba
    #8 BigTex, Dec 9, 2004
    Napolis is right....find a guy who can PROPERLY set it up....starting at OEM is a good start..

    Mine, with ANSAs had many issues before we did that.
     
  9. 1975gt4don

    1975gt4don Formula Junior

    Nov 5, 2003
    665
    Peoples Rep of CA
    Full Name:
    Smog Exempt
    #9 1975gt4don, Dec 9, 2004
    Amen! I have my air injection where it belongs: hanging on a wall in my garage. It looks rather nice there as well as my thermoreactor muffler leaning against the wall collecting cobwebs. You could run a car if you tailgated me close enough behind my GT4.

    Ah, the joys of having a 75.


     

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