Put in bigger cam now car stalls in gear

Discussion in 'Street/strip 400/430/455' started by MDCH, Aug 18, 2017.

  1. MDCH

    MDCH Well-Known Member

    Hi ever one I have just done a 430 rebuild and installed a bigger cam.


    Now the car stalls when put in gear at normal rpm. I have a new Holley XP 750 on it and had a micanic look at it . He suggested I may need to put a higher stall converter on it. It has the original stall converter on it ( possibly a switch pitch but all the switch gear is missing).

    Please help. :confused:
  2. Bigpig455

    Bigpig455 Fastest of the slow....

    the 212 isnt THAT much cam....I'd take a look at your mechanical advance/initial distributor timing, etc...You might find that you've got too much mechanical advance at 700-900 rpm.
  3. shiftbyear

    shiftbyear Well-Known Member

    your car should idle with the throttle blades nearly closed, it should look like the picture from underneath. holley tech line should have some answers especially for what they charge nowdays for a carb, have you checked vacuum at idle and in gear. as Rhett said it's not overcammed so tuning with mixture screws, air bleeds or timing should get it corrected. good luck

  4. MDCH

    MDCH Well-Known Member

    Thanks gents Ill do some more work and get back to you.
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Running more initial timing can help a lot. Do an experiment. With the car idling in Park, advance the timing up to 20*, and then put it in gear. If that makes the difference, you will need to reduce the amount of mechanical advance accordingly.
    techg8 likes this.
  6. buick64203

    buick64203 Just plum crazy Staff Member

    You might have to close the primary throttle blades and open the secondaries more. There is a set screw to adjust them. My 308S idles at 800 in gear
  7. Jim Rodgers

    Jim Rodgers Well-Known Member

    Hes right. Converter.
  8. buick64203

    buick64203 Just plum crazy Staff Member

    Converter really? but its such a small cam:confused:
  9. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    If all else fails, check for a vacuum leak if the intake was removed to replace cam. Or a carb related vacuum leak. GL

  10. TA Perf

    TA Perf Member

    Do a compression check. Sounds like she's low on compression. Cam timing can cause low cylinder pressure as well. See where your at.
  11. matt68gs400

    matt68gs400 Well-Known Member

    There's no way that car should stall with that cam and a stock converter. I had a small cam and stock converter. Ran great in park and in gear at a stop light. Now I have a higher stall converter. No difference.
  12. BuickV8Mike

    BuickV8Mike SD Buick Fan

    The problem likely isn't the stall converter or cam.
  13. Stampy

    Stampy Well-Known Member

    I run almost the same cam, on a stock, 50-year-old, low-stall converter. Really does not sound like a converter issue to me, especially on a new rebuild with a new carburetor. So many other variables here. Was the camshaft checked with a degree wheel? What's your initial timing? Where is the idle set at in park? Is your vacuum advance hooked up? Which vacuum advance canister are you using (should be a B-XX stamped on it, where XX is some integer)? How much vacuum is the engine making at idle, in park? How much total advance do you see at idle, in park? Is your engine making enough vacuum at idle to properly engage the vacuum advance? What's your confidence in the carburetor settings being "close enough"?

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