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Thread: Low Lift Flow?

  1. #1
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    Default Low Lift Flow?

    Speaking of flow in the .300 to .500 range, if a different head has say 30 to 40 more cfm in that range, what impact will that have on the performance?

    23* stuff, all other things being equal. Lift is in the .670 range, durations in the 264 range.

    I would say more torque and HP, but would it make the engine spike to fast or impact the curve a lot?

    Thanks, Krom
    Last edited by Kromulous; 01-21-2021 at 09:17 AM.

    Just say no...

  2. #2
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  3. #3
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    Default

    I think generally speaking if a head has the same flow number at higher lifts but more at lower it is a sign of a overall more efficient port and that should equate to more power and more power longer

  4. #4
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    Tell you what i am looking at. We have a 430 with 227 cc CNC ported Dart Pro 1 heads on it. Engine made like 640 hp not sure of the torque, but it was decent. Its not enough.

    Anyway, wanting to make some a upgrade on the heads, but we're on a tight budget of course LOL. I found some older sprint car heads, friend of mine has them. They are the Brodix -10RI the "Jones" 240 port ported by Weld Tech. So i am trying to make the best decision to upgrade or not.

    Looking at the numbers, the Brodix heads are far and away better with 40 or more cfm at .400 and on, with about 25 cfm on the exhaust side. Cross sectional area is slightly smaller, and the port overall size is 240 cc, which is slightly bigger.

    Keep in mind i dont want to go to far, i am wanting right around 700 hp, and would like to make the powerband wide and smooth.

    Just say no...

  5. #5
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    Default

    krom , i would think that dart head on a 430 should easily make that HP number , what cam are you running?

  6. #6
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    The -10RI is a better head & your 430ci can definatly use it.However I don't think you are getting the most out of your Dart Pro1 heads.640 hp is way short of what a 430 with that head is capable of.Don't know why but it could be camshaft,rockers,intake or compression but something is not working like it should.640hp from my 362ci with a ported Dart 200 head is normal.You should be seeing 700hp with that ci & that head.

  7. #7
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    Thanks guys, the intake is a unbranded single plane not sure what it is LOL. The cam i will find out what exactly it is, we bought the engine off a friend of ours and it runs fine don't get me wrong, but it just short of what we need.

    Compression is like 12 to 1, Going to bump it up to 13:1 maybe more.

    Intake 2925 CNC ported, or the newer Super Victor 2892 i think it is?

    Then i'll find out what the Cam is, what kind of duration should i be at? 264 to 268 range on intake?

    Just say no...

  8. #8
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    If I were going to change intakes I would put on a ported Brodix BM1000.Camshaft depends on rocker ratio but for that size engine 264* @ .050 w/1.7-1.7 rockers ground on 108* & installed on 102* will work.But be careful on camshaft.I can have a Comp Cam roller ground with 264* @ .050 with about 10-12 different profiles from mild to radical.In your case a TK series and keep it under 8000 should work.put about 272* @ .050 on exhaust.

  9. #9
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    Perfconn, do you know where i can get a ported version?

    Rockers are the typical 1.5 /1.6 i think on the intake side i believe.

    I will say on the engine, the cam is not right, we had to stack gear in it and crank it to 8700 most of the time to keep up. The engine has really good parts in it, so i am not scared of the rpms, but that tells me its not right. We dropped a cylinder on our last race, i think we beat the seats out of it, stainless valves.

    Just say no...

  10. #10
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    Try Joe at HVH.He is a Brodix dealer.I wouldn't turn any engine 8700 with stainless valves.After 7700 on a 4" stroke you will start jerking wristpins.All engines have a critical piston speed.After that you will have trouble,its just a matter of time.Really good parts break too.

  11. #11
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    I know, borrowed time. We will get back inline with where we need to be.

    I may just call you if that's ok to get a proper cam, will get it apart shortly to see what i got.

    Just say no...

  12. #12
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    Default

    Perfconn, you every use the TK455 lobes?

  13. #13
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    Not my favorite lobe,but yes I have.I prefer more rocker & less lobe.Lift may end up same at valve but I think and have found that less lobe lift is easier on lifters.

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