What Carb to run on my full roller 355?

Discussion in 'Engine Topic' started by ddc456, Dec 6, 2011.

  1. 5spd540

    5spd540 Veteran Member Lifetime Gold Member

    Sep 19, 2009
    Guyton, GA
    My brother in law has about that same set ip with a 750vs holley 3310 on his
  2. K5JMP

    K5JMP Veteran Member Lifetime Gold Member

    ^yup. I run a pair of 660 center squirters on a tunnel ram:smokin:
  3. dubs74camaro

    dubs74camaro Veteran Member

    Mar 19, 2011
    Big Block, OR
    Okay.....I'll split the difference. Run a 700!

    It takes a well prep'd 350 to truly need a 750 DP. I'm assuming your 2.02 heads are older iron ones which don't flow like todays heads. That's not a really big cam. The problem with guys that do run 750s (holley) on a 350 and says they run well have probably never tried an 650 or so on there. Once the motor cleans itself out in the upper rpms they really feel this surge in "power". Problem with most street engines is we don't stay at 5,500-6,000 in RPM. You have a slight delay in the startup of the main circuit with a 650 due to the straight leg booster being positioned a little higher in the venturi. That makes it a little more forgiving carb down low. That combined with the slightly smaller venturi gives you a better streetable throttle response. I have ran both a 750 DP and a 650DP on my 454 BBC. The 650 on MY combo flat runs quicker and better. I also have you by 100 cubic inches though the R's are down a bit. Bottom line is the hardest thing to ever convince a guy of is that he will need less cfm than he THINKS he needs.

    Just remember the massive power these restricted classes make with a 390 double pumper and a 500 2 barrel.
  4. warped

    warped Veteran Member Lifetime Gold Member

    A vacuum secondary carb will be more forgiving if you buy larger than your engine really needs. From the info given, I would say something like a 650 (maybe the 670 Street Avenger) would be a better choice than the 750.

    If the car is mostly street driven, you would be better off with the vacuum secondary carb than the double pumper. You have the manual trans, but if your rear gears are not large enough (numerically -- 3.42 or 3.73 for instance) the double pumper will be less responsive and use more gas. Good luck.
  5. hhott71

    hhott71 Veteran Member Lifetime Gold Member

    Mar 30, 2001
    Joplin Mo. 64801
    .480" 230º cam is a flat tappet cam, Comp HE280 cam (and many others).
    The 650 is MORE than plenty. That cam noses over about 6000 rpm
    The Iron 2.02 heads flow OK with that cam, a set of good Aluminum heads will knock off 4/10's of a second.
  6. ddc456

    ddc456 Veteran Member

    Oct 11, 2010
    Barak Obama has added $5 Trillion to the United State's national debt in less than 3 years
    -- and $1 Trillion of that is just his green's fees!

    This may have been the best thing i have ever heard!!!

    Hey thanks for the input guys, it's nice to know where we can go for help and not get screwed now adays!!!!
  7. dubs74camaro

    dubs74camaro Veteran Member

    Mar 19, 2011
    Big Block, OR
    How the heck did politics get in here?
  8. Tokyo Torquer3

    Tokyo Torquer3 Veteran Member

    Oct 14, 2003
    A 650 vacuum secondary cam will be plenty for that motor and the vacuum secondaries will be more foregiving and better gas mileage.
  9. woody80z28

    woody80z28 Veteran Member Lifetime Gold Member

    Sep 8, 2004
    walton, ny usa
    I have the exact cam, compression and CI, but with Vortecs. And I can tell you right now the 750 and the 600 I've had both had their strengths and weaknesses. I spent a couple years trying to get the most out of my 600 at the strip, and my very first run with a 750 gained 3mph. But...the 750 is a little lazier down low and doesnt have quite as much throttle response at half pedal.
  10. dubs74camaro

    dubs74camaro Veteran Member

    Mar 19, 2011
    Big Block, OR
    Well I tried to google and wiki it. No luck! What is this thing "gas mileage" that so many of you seek? lol

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