Air Bleeds Sizes

Discussion in 'Race 400/430/455' started by Rick Henderson, Aug 29, 2002.

  1. Rick Henderson

    Rick Henderson Well-Known Member

    I have a Holley 4150 1000cfm carb and the front air bleeds are 49 and the back are 65. Can someone help me out with this? Too much, not enough?
    My 455 has around 9:5 to 1 compression with forged pistons. I have a healthy cam in it, Sp1 intake, with Greg Gessler heads, and I drive it to the track and run 12:20's or so.
    Thank you,
    Rick Henderson
     
  2. Da Torquester.

    Da Torquester. Platinum Level Contributor

    Rick, If you still have your stock air bleeds that came with the carb I would start with those. The last issue of CC. says to leave em alone unless you have access to a dyno. with an exhaust probe analyiser. Just my .02
    John
     
  3. Buicks4Speed

    Buicks4Speed Advanced Member

    ???

    The 2 inside air bleeds on the front and back should be the same. The "49's" should be on the inside front and back and the "65's" should be on the outside front and back. The 65 air bleeds are for your idle and the 49's are you main air bleed which is your driving/power circuit in your carb.
    I don't know what is suppose to be in your carb originally but the 49's sound a bit big. If your carb is lazy at wide open throttle and it keeps going faster with more jet than you should try going smaller on your air bleed. My rule of thumb is if you need to go more than 4 jet sizes larger you need to go smaller on your air bleeds.
    Stock jetting on that 1000 if its a down leg booster style carb is 84 on all four corners. If its a annular booster carb the jets are 84 in the front and 88 in the rear. My book does not have the original air bleed size listed.
    Most of the HP holleys I've seen have air bleeds in the upper 30's and low 40's on the main curcuit. 65 sounds about right for the ide curcuit. If your idle mixture screws are 3/4 to 1 turn out from all the way shut for best idle than you should probably go 3 to 4 sizes larger on your air bleeds only on the idle curcuit, (the outside air bleeds).
    12.20's sounds a bit off. Whats you mph? I built a 71 skylark with a 455. Street car, pump gas, 230/244 112 LC cam, 950 HP carb w/ 1" spacer, and it ran a 11.74 at 114 with a 1.69 60 ft on Mickey Thompson sportsman pro street tires. I would think you should be in the 11's possibly low 11's unless your running radials.:Do No:
     

Share This Page