The great nailhead intake comparison

Discussion in ''Da Nailhead' started by 66gsconv, Mar 12, 2013.

  1. Bigpig455

    Bigpig455 Fastest of the slow....

    Looks Great! Pretty similar to the DDP I did on my square bore before I put together the Q-Jet set up....I keep forgetting, but that ran well too, even with the AFB. I ground those dots off the floor of the plenum on both mine - should I have left them?

    I've got two 1/4 inch base gaskets I've been thinking of glueing together as a 1/2 spacer, should work although Tom says I cant use RTV to join them - I'll have to find some other "adhesive" - Silicone sealer?

    Did you ever do any before and after testing with your spacer?
     

    Attached Files:

  2. 66gsconv

    66gsconv nailhead apprentice

    Rhett, I have to run a spacer as a adaptor. As Doc always says he makes his own, I was a little lazy and called summit and order two 1/2" alum. 4 hole spacers. I cut one of the out and made a open spacer out of it. They are 12 dollors each. Now all my testing was by seat of the pants. I felt the 4 hole didnt do much, when I put the open one on I felt it didnt loose any low end and did help the mid and top end. So that is what I have been running ever since. Doc has been kinda quite, mabey a 950 holley will wake him up :)
    [​IMG]
     
  3. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA


    Hey Rhett,you can't use silicone because it isn't gas resistant,you could use a thin layer JB weld to bond the 2 together,if JB weld can fix gas tanks,it should work for that.:TU:


    Derek
     
  4. Bigpig455

    Bigpig455 Fastest of the slow....

    Overkill - Thanks and good suggestion, but I would think JB weld wouldnt "flow" out for a flat seal, and would have high spots.

    I was thinking maybe 2 part epoxy, but that just seems like it would be brittle when it's dry. I'd want something that dries a little more pliable, even though it will be sandwiched stationary.

    Keep those suggestions coming please!

    ---------- Post added at 09:38 AM ---------- Previous post was at 07:42 AM ----------

    Next question -

    As I put the spacer together, I have the option of mating two 1/4 inch 4 hole gaskets, two open gaskets, or one of each. My initial thought was use a 4 hole next to the carb base, and an open gasket beneath it. That would preserve velocity on the upper end, yet give the charge more room to turn on the lower end.


    Now if you look at the picture of my square bore manifold a few posts up, I'm a little concerned about letting the charge go free above the sharp edges of the manifold carb pad - would that loose velocity and direction? Or would it give the charge a chance to equalize (like is allowed by the channel in the secondary center divider??Would using two 4-hole gaskets keep the charge channelled into the manifold better, and the DDP take care of the turn below the carb pad?

    What are your thoughts? I hope I've explained this clearly....

    Thanks!
     
  5. 66gsconv

    66gsconv nailhead apprentice

    Rhett, I run a doc dual plane and a holley. So I have to run a adaptor and I used a 1/2" 4 hole and then tried the 1/2" open. I feel the open gave better results. Could be defferant with the q-jet.:TU:

    ---------- Post added at 10:59 AM ---------- Previous post was at 09:23 AM ----------

    Also Rhett, so far your the only one that I know of that has done back to back 1/4 test with the DD mod. All this air flow numbers might not mean crap. You dont know till you do some testing like you did. But it does give some idea what is going on. I expected to see better numbers with the EELCO, I was surprised. Tom and Doc always say dont underestimate the 1x4. What started this thread was I wanted to see what could be done with the 4 holes still in the intake. And it kinda snow balled from there.
     
  6. gsgtx

    gsgtx Silver Level contributor

    with the intake porting with docs mod or Bobs mod, with Rhett testing it and what everybody says, its seems good for 1 or 1.5 tenths, thats good for a stock iron intake. when i went from stock intake on my 440 mopar to a edelbrock rpm performer it was worth 3 tenths and 3 mph, plus some weight savings.
     
  7. wkillgs

    wkillgs Gold Level Contributor

     
  8. Bigpig455

    Bigpig455 Fastest of the slow....

    Walt - I'll use both 4 holes and see what I get. Spend some time with Tom and you start to get real protective of swirl and velocity on these cars.......

    I'm gonna go out on a limb and call the Doc Mod good for two tenths. It's so hard to be precise, because on any given day your ET's could swing .3 either way! At the time I did the AFB square bore DDP, I was making one change at a time and measuring on the street with my G-Tech meter. But the last couple years I've been making a few changes at a time and using my timeslips from Lebanon to really nail it down. So all the Q-Jet mods are kinda "grouped", but collectively made a big difference.

    BUT... today I broke out the G-Tech again to measure some recent work, and had some very revealing results. I wont give it away, but they're more tranny related and will be covered in the other thread.

    I'm looking forward to this season, I think my first outing will be Friday May 3rd, there's an all day track rental at Lebanon Valley. it's a great deal - 70.00 to make all the runs you can fit in, no waiting, two drivers allowed. If the weather is good, I just might make my 14.5 pure stock (on the Q-Jet and 3.23's) - keeping my fingers crossed anyway. Anybody who wants to join me, PM me and I'll give you the organizer's name to sign up.
     
  9. 66gsconv

    66gsconv nailhead apprentice

    Walt, nice job on the intake. Have you run that intake on a car yet?

    Rhett, I dont know if nailheads just like q-jets, I think its the single carb set up. My 2x4 runs really good, But I had no way to test the defferance. But I love the way my 1x4 revs and runs. Must be something to do with the velocity:Do No:
     
  10. bigds65

    bigds65 Well-Known Member

    Bob,
    Your in box is full.:Brow:
     
  11. GS Jim

    GS Jim Platinum Level Contributor

    Hi Guys. I hate to break in here with a different question. Does anyone know what the original Q-Jet from '66 ran as far as CFM? I have a carb and a couple intakes and was just wondering.
    Thank's

    PONCH
     
    Custom65GS likes this.
  12. gsgtx

    gsgtx Silver Level contributor

    i think its 730 cfm
     
  13. wkillgs

    wkillgs Gold Level Contributor

  14. 66gsconv

    66gsconv nailhead apprentice

    Wow, a guy could have some fun grinding on that thing:Brow:
    My Doc dual plane looks just like everyone elses, nothing special.
    Walt, does your hogged out q-jet have good low end? Just wondering how it worked for you.
     
  15. doc

    doc Well-Known Member

    :Brow: Three barrel ??? Somebody say something about a 3 barrel ?????:Brow:
    HMMMMM,,,,, I tend to think that spreadbore intakes/carbs lend themselves more to street driving ,,, where 4 bore and 3 barrel intakes/carbs are more pure performance set ups.... Ie holley 3 barrels and 4500 series carbs...but,,,, and everybody has a but,,,:Brow::Brow::laugh: what you have to do is think about and analyze the Total combination of the car....the cars weight/diff gearing/trans gearing/ air intake/ ect... I favor vacume secondaries on a carb.. for a reason... the engine can ''signal'' when it wants more fuel/air based on all the above variables....
    any given car will act differently with a certain carb/intake combo if the diff gears are changed.... for instance... or the wt. is changed.... or tire change....
    the only way to positively sort out the carb/intake combo power figures is on a dyno under controled conditions... and that takes big bucks....
    now all I am waiting on is for holley to make a 4500 three barrel:Brow::Brow::pray::pray::laugh::laugh:
     
  16. 66gsconv

    66gsconv nailhead apprentice

    Ok, Tom T called the other night and asked what I had on a stock head:idea2: I knew I forgot somthing:Do No:
    Soooo.. I found a nice looking stock valve and threw in on the bench. I was surprised that this runner had such good numbers at .100 and .200 lift so I checked for leaks and retested it 3 times. Some reason it got better # at them lifts than other ones I was used to They almost always come in around 59 to 64 at .100 and 112 to 118 at .200. Must be a really nice valve. Also its been a long time since I flowed a stock runner and had forgot how noisy it is, as in turbulance. This tells us a lot and also doesnt really tell us a damn thing, mabey a few cfm by doing a Doc dual plane gets us 2 tenth and a nailhead is as Tom always says is " asmahtic". Not spelled right so I will just say " cfm deprived"...:laugh:
    Anyway here is what I found
    1- stock head
    2- stock head with well placed clay around intrance
    3- head with stock sqaure bore # 1 runner upper plenum
    4- head with stock sqaure bore # 8 runner bottom plenum
    5- head with bobs square bore # 1 runner upper
    6- head with Bobs sqaure bore # 8 runner lower
    7- head with doc dual mod on a q-jet upper
    8- head with Doc daul mod on a q-jet lower
    9- head with eelco upper plenum
    10- head with eelco lower plenum
    -----1-------2-------3-----4------5------6------7------8------9-----10
    100-68-----69-----68----69----70-----70----70-----69-----71----71
    200-126---127---124---121---126---124---125---122---127---124
    300-155---168---156---149---159---155---157---151---158---154
    400-167---181---168---161---172---169---171---162---171---167
    500-171---188---174---167---178---175---177---167---178---172
    600-175---192---177---169---182---178---180---170---181---175
    I hope this is understandable, not much air with the intake on. Also I do want to point out that the intake with the doc job on it is not ported anywhere else. Now we need to get drag srip testing. I hope this summer to do a little
     
    Last edited: Mar 23, 2013
  17. 425 2X4 Nailhd

    425 2X4 Nailhd Well-Known Member

  18. 66gsconv

    66gsconv nailhead apprentice

    Ok, just spent some time and fixed my first post. For those of you that like this kinda stuff I hope it is understandable now. It looks like you get a little cfm by doing the Doc job but a little must be a lot on these engines, we know Rhett gott .2 tenth with back to back test. It would be nice to have a dual plane intake that would keep up velocity and still feed the air that the intake runner is capable of flowing. :Smarty: :idea2:
     
  19. doc

    doc Well-Known Member

    Well,,, as you do these mods, the dynamic shifts,,,, it goes from the intake manifold being the restriction, to either the heads being the restriction or the carb being the restriction.... when we get the optimum set up, it will finally peak out untill another idea comes along.... the least restrictive that I can think of was the old man-a=fre system that was so bad to catch fire.... but it was not restrictive.... It would burn your car for you but did not restrict the engines intake...:laugh::laugh:
    I would think that the ideal set up would be to get the head/intake combo to flow more than the carbs restriction would be the ideal goal.... thas why I like my big holleys:Brow::grin: that said,,, :idea2::idea2:
    To me a intake that was port matched to the heads, ddp modded, and then extrude honed would be just about the optimum set up .... the only other improvement would be if it were made of alluminum...:idea2:
    you guys have done some excellent ''home porting and relieving'' work as evidenced by the pics,,,, and have had good results from the reports I have seen ,,, makes me real proud and satisfied that the ddp idea has turned out so well.... :grin:
    but it would not have reached its full potential unless you guys had not used your smarts and skill to make it happen....
    I dont understand all I know about flow benches ect.. but I do know that a guy in his garage with a good mind and some tools forms the back bone of the hot rod movement.... and that is a good thing.....:laugh:
     
  20. gsgtx

    gsgtx Silver Level contributor

    Bob, i think you should let me test your Bobs sq bore intake, when you send it, please FORGET to put the return address on it.:laugh:
     

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