Looking for advice: 4150 or 4160?

Discussion in 'Holley' started by 69GS430/TKX, Apr 20, 2011.

  1. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    Hey everyone, I am a newbie here. Of all the GS Skylarks (and one RivGS) I have owned, the only one I have held onto is my first one from high school--a 1969 GS400 with a balanced, very-high-compression '69 430 (bored .030 over) full of Kenne-Bell guts and the original Muncie 4-speed. When I bought it in 1977, it had a Holley 650 double pumper that was very responsive but ran out of gas after a few seconds of acceleration. So I tried an 800 Thermo-Quad and didn't really like it. Ditto the Quadrajet. So I am back to trying Holleys. I have a 4781-2 (850 cfm, mech. secondaries) and a 3310-2 (750 cfm, vac. secondaries).

    Before I rebuild them both, I was hoping those of you with more experience running Holleys on Big Block Buicks could help me decide which of the two will make me happier when I go through the gears on the country roads. I don't race, and I never take the beast over 5000 rpm because that last engine overhaul I did is the last one I ever want to do. What are the drawbacks of 4160 Holleys compared to the dual-metering-block 4150s?

    Thanks in advance for your ideas! I love this site.
     
  2. 462 Chevelle

    462 Chevelle 462 chevelle

    i think the 4 corner idle is best if you have a huge cam and your trying to get vacuum out of it or make it streetable. but im not exactly sure. i would say use the mechanical secondaries 850.
     
  3. 69GS430/TKX

    69GS430/TKX Silver Level contributor


    Thanks, Lonnie, I was hoping that would be the right answer because I think this engine can use all the gas it can get. I am running a Window Rattler for a cam, and I don't know that vacuum is a major issue since the car has no power brakes. Nor power anything else, for that matter, except hopefully engine. :grin:
     
  4. doc

    doc Well-Known Member

    Have you ever considered one of the holley nascar three barrel carbs that were made in 1968 and 1969....???? they came in 950 and 1050 cfm, with vac secondaries.... I am running a 1050 cfm on my nailhead... and have in the past run a 950 cfm on the same engine... the engine runs strong with these carbs...
    I t is nice to run a carb that will just bolt on and has big performance without multiple carbs or a dominator.....
    dont forget to modify your air cleaner assembly for more flow.... it amazes me that the factory puts a carb on with 4 holes in it and then has it breathing thru a air cleaner snorkel with one little 1 1/2 in. hole in it...:laugh: :laugh: If you dont already have it, a cold air intake is worth a lot of power, as is my Doc dual plane mod... and recurving the dist.... cheap , perminate , power all......
     
  5. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    Thanks for taking the time to post, Doc. Yes, I would love to give the old Holley 3-barrel a try--I have heard great things about them, ditto the Dominators--but for now I am stuck with the carb choices in my "inventory." The intake on my GS is a B4B, ported & polished in the right places along with the rest of the respiratory system of the engine. If I don't like how this 850 works, maybe I will try to get my hands on a 950.

    I do have another question: I want to put a phenolic spacer under the carb because this motor makes heat like crazy. Should I use the open-pattern spacer, or the 4-hole one?

    Thanks for all the insights you can share. I want to get this high-school car on the road before I die of old age. It's been in storage over the past 30 years more than it has been in use.
     
  6. doc

    doc Well-Known Member

    If it is a thin spacer a open one would be ok.... but if it is thicker then you would need the 4 hole type... personally I have the ole Doc dual plane mod done to my intakes so I take a 4 hole and make it into 2 ovals front to back to match the manifold.....
     
  7. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    Ah, I see. Your mod sounds like a good idea. What kind of tool do you use to remove material to get it to that shape?
     
  8. doc

    doc Well-Known Member

    Just go to ''da nailhead'' section and check out the sticky there ... pictures and all........
     
  9. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    Sorry I didn't get back sooner to say thanks again, Doc.
     

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