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Thread: Problems....

  1. #1
    Member JOURNEYMAN
    Join Date
    Jan 2008
    Location
    Newcomerstown, OH
    Posts
    33

    Problems....

    ok, I put a lunati bracket master cam in my 350 sbc. I have the valves close to being at the right lash. but I am having problems with my carb. It is real rich at idle and really lean at WOT going down the track. I have around 36 total timing. I idle with about 3-4 with vacuum, but when I rev it up in park (no load on motor) the vacuum goes up around 10-12. I run a power valve in a 750 holley DP. I believe it is a 6.5, I know it isn't right for the motor now and that is probably why it is rich at idle. Why does my vacuum seem to work backwards?? Does the motor have to under load for the vacuum to go down?? Any help is greatly appreciated.

    Thanks,

    Travis
    72 chevelle, tubbed. 350/TH350. Best 8.29@83mph w/100hpNOS 7.72@90mph
    67 Chevelle SS clone 396/TH400
    00 Silverado 1500 ext. cab long bed. daily driver/tow rig
    88 Camaro 305TBI
    81 Malibu Wagon 327/TH350

  2. #2
    Senior Member DYNO OPERATOR
    Join Date
    Aug 2005
    Location
    Rifle Colorado
    Posts
    585
    Yes it has to be under load for the vac to drop, or a wot. I'd suggest under load......with 3-4" at idle, I'd suggest a 2-2.5 pv or block it off. Why do think it's lean down track?

  3. #3
    Member JOURNEYMAN
    Join Date
    Jan 2008
    Location
    Newcomerstown, OH
    Posts
    33
    I have an air/fuel ration gauge. cheap digital summit one and only the bottom 1 or 2 lean bars come on. The car just feels like it doesn't have much power, it doesn't pull. I have been shifting at 6000. only 60ft at 1.93. Was at 1.7 last year with blue racing 465/488 lift cam. It only ran a best of 8.63 at 78mph. Laster year was 8.2 all day long.

    I have 5.14 gears, 4000 stall converter and 30x14 rear tires.
    72 chevelle, tubbed. 350/TH350. Best 8.29@83mph w/100hpNOS 7.72@90mph
    67 Chevelle SS clone 396/TH400
    00 Silverado 1500 ext. cab long bed. daily driver/tow rig
    88 Camaro 305TBI
    81 Malibu Wagon 327/TH350

  4. #4
    Try going up 3 or four sizes on the jets, to richen at WOT, then you can take the idle mixture screws and lean out. The correct power valve will also help


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