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SBC guys...need input on 327.Paging Engine Pro 5X

Discussion in 'The Hokey Ass Message Board' started by fleet-master, Nov 23, 2012.

  1. fleet-master
    Joined: Sep 29, 2010
    Posts: 1,765

    fleet-master
    Member

    Hi guys , I'm hoping you guys can help me decide on which intake and carb I should use on my 327. I'd like to end up with a nice crisp street engine probably not a daily driver ...the specs are as follows;

    block casting: 3858174 (1966 327 far as I can tell)
    crank number: 4577
    heads : 3917291 (1.94" / 1.5" )
    cam (current): C1H 284S (general kinetics ?)
    diff : 3.5:1
    rear tyre : 26" tall

    the engine currently has an Edelbrock SP2 P intake and Holley list 80137 carb

    I'll probably be running it in my F1 for a bit then swapping it into my track roadster.But thats another time. Many thanks in advance for your help. PB :)
     
    Last edited: Nov 23, 2012
  2. slick377
    Joined: Nov 7, 2007
    Posts: 115

    slick377
    Member

    Dude, don't go any bigger than 650cfm, best all round will be a good old 600 vacuum secondary list #1850, or best performance will be 600cfm list # 4776, or 650cfm double pumper list #4777, rule of thumb is smaller choke size gives better acceleration or torque, bigger gives more top end HP- at the loss of bottom end performance. The heads you have there wont flow a whole lot with out some major work so a big carb won't do anything except cost you torque and fuel.... hope that helps
     
  3. fleet-master
    Joined: Sep 29, 2010
    Posts: 1,765

    fleet-master
    Member

    anyone else? Squirrel?
     
  4. kennkat
    Joined: Aug 25, 2011
    Posts: 1,384

    kennkat
    Member

    Ahh Baloney. A F-1 Ford is a fairly lite truck... if just a hot rod. You could easily use a 650 vac carb there. I have had good luck with the 300 - 36 holley intake in this sort of application. When in the roadster these parts will work well too, but you could get a bit more performance with a 4777 Holley double pumper here... Either way a GOOD Ex is a Must!! That's just my opinion after 38 years in this biz...
     
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  5. fleet-master
    Joined: Sep 29, 2010
    Posts: 1,765

    fleet-master
    Member

    Thanks guys. What exactly is the SP2 P intake? I've been told it was introduced as a factory replacement manifold from memory. How does it compare to say a Performer or Performer RPM?
    Is inch and five eighth the optimum size for primary header pipes?
    My questions are a bit rudimentary I guess but I'm a body guy..no mechanic
     
  6. kennkat
    Joined: Aug 25, 2011
    Posts: 1,384

    kennkat
    Member

    The SP2P is a POS, in my opinion...
    Performer... Performer RPM, better choices, as the name implies the RPM model is a little more "RPM worthy"
    1 5/8" is a good all around performance tube diameter for a under 355" street chevy...
    My opinion after 38 years of building these critters...:):):)
     
  7. Deuces
    Joined: Nov 3, 2009
    Posts: 17,792

    Deuces
    Member
    from Michigan

    The #291 heads came standard on the '68 302 engine, but with the bigger 2.02/1.60 valves...
    I think they're good heads...;)
    They just need some valve work....
     
  8. kennkat
    Joined: Aug 25, 2011
    Posts: 1,384

    kennkat
    Member

    :)Correct! Just enlarge the Ex to 1.6 when putting hard ex seats in.... modify the port to provide the largest "short side" radius... with the best "line of sight" at the backside of the valve as viewed from the ex port flange.... without excessive volume increases. Aside from the bowl area directly under the intake valve head, the "push-rod neck" of the intake port is another important area to pick up flow without losing velocity...:)Keep the Int valve size to 1.94 if possibile, but rather than put in intake valve seats put in a 2.00 intake valve if needed to avoid "sinking" the valves. This loses flow in nearly every case I have ever seen....Just my 38 years of Hot Rod Experience talking.:)
     
  9. Deuces
    Joined: Nov 3, 2009
    Posts: 17,792

    Deuces
    Member
    from Michigan

    I've been at it for 38 years also.... :D
    Damn, I'm gettin' old...:(
     
  10. I think I understand your idea. I'd choose a spread bore carb.
    And a z28 type manifold.


    Your sp2p intake is going to build low end torque by using small runners to increase the velocity. Its generally done by 4000 Rpm on a 283 so I'd guess 3500 on a 327. This intake might makeup for some of the loss on the low end from the 284 cam.

    Your cam is going to be heading onto its peak right when then manifold is done. Will also need at least 2500 rpm converter or manual trans.

    So the current cam and intake don't match each other,
    But I guess it ran OK at a narrow rpm window and never made anybody happy like that
     
    Last edited: Nov 24, 2012
  11. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,912

    need louvers ?
    Member

    if I remember correctly, the SP2P came out of the mid seventies and the gas crisis need for better economy. As '31 Vicky said above, right now your cama nd manifold are gonna be at odds with each other. I didn't catch what trans your running, but about the sweetest 327 I have ever pedaled personally ran a similar cam with a Wiend single plane intake and a Holley 600 cfm vacuum secondary carb. Usually a single plane like that is happiest in a stick type situation, but in the lighter stuff you describe it should be happy with an auto to.
     
  12. Larry T
    Joined: Nov 24, 2004
    Posts: 7,675

    Larry T
    Member

    I'm gonna guess the 284 in the cam number is advertised duration. That is gonna put the sweet spot around 2500-6000 rpm (about normal for a "hot" street engine). But the SP2P intake doesn't match up very well with it (SP2P is designed for off idle and low rpm use). I'd go with a Z-28 clone intake. Performer RPM is probably the most common now days, but there should be some used manifolds floating around too.

    As far as carbs go, I'm not a big fan of the Holley spreadbore and if you're gonna change intakes now would be the time to change. I'd go with something between 600-650. I don't think there will be a major difference in performance between a Holley and an Edelbrock/AFB. Just pick your poison.
     
  13. rustang
    Joined: Sep 10, 2009
    Posts: 710

    rustang
    Member

    With that 2500-6000 rpm cam, and those heads, I would go with a Eddy RPM or RPM Air Gap, and a vac secondary carb (Holley or edelbrock) nothing larger than 650 cfm (I personally would go for a 600cfm)......put some advance in the ignition, and let 'er snap...

    You will want some stall in the convertor if an auto, or a better yet a 3 pedal .
    Tom
     
  14. oj
    Joined: Jul 27, 2008
    Posts: 6,155

    oj
    Member

    Get a different carb/intake combo for the truck and hot rod. Don't think that one combo will satisfy both requirements. Use the intake you have with a vacuum secondary 4bbl or throw an edelbrock on it for the truck. Start saving up for a better combo when you put it in a hot rod. When it is in the truck the carb needs to be a worry free device that sits between the intake and air cleaner, right? When the engine is in a hot rod the carb(s) are the centerpiece on your coffee table and you have to satisfy a higher set of requirements.
     
  15. Good Morning H.A.M.B.ers. I'll see if I can help you here with this. I'have never cared much for the SP2P manifold as it was a crazy attempt to make poor built engines get good mileage and nothing else. In the manifold department if you are wanting traditional use an Edelbrock C-3B. And if you want the new look I have always liked Weiand so in this case I would choose a Weiand Stealth.Now for the carb I always ask my customers this. Can you tune a carb?? I you can tune a carb run a Holley if you can't tune a carb run a Carter or an Edelbrock. Now to the camshaft. I'm thinking the 284 # on the cam means it will have 284 duration. This is more than I would try for a sharp crisp engine however if I could see tha cam card and know how it was degreed into the engine I could add more to that. And as usual it will need a good ignition system, valve springs, along with good exhaust system. I hope this helps >>>>.
     
  16. saltflats
    Joined: Aug 14, 2007
    Posts: 9,558

    saltflats
    Member
    from Missouri

    I would go with the performer not the RPM it has smaller runners better match for small engine. Try and find a 600 or 650 carb with down leg boosters for better throttle responce IMO. Probably a little to much cam for a crisp street engine of that size.
     
  17. raengines
    Joined: Nov 6, 2010
    Posts: 227

    raengines
    Member
    from pa.

    the sp2p was junk and nothing else, any of the 350 or 365 hp gm intakes are very good. z28's used the same ones, the 350 hp hydrolic cam ending in 151 part number was one of my favs back in the day and I installed lots of them for friends. the good old days lol.
     
  18. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,124

    porknbeaner
    Member

    I am with Enginpro on the intake choice, if newish is not a bother another good choice would be a Holley Contender, the down side to the contender is that it likes more air to keep the plenum full so a 650 to 700 cfm carb would be a must.

    If I had to go with an edelbrock intake I would look for a tarantula to go with the cam, given that our assumptions on duration are correct.

    I am not sure what your definition of crisp is, if you mean that it sounds mean off idle and the carb makes a lot of air noise then you want a smaller camshaft and carb combo. If you can live with revs then you just need to match an intake with your camshaft and keep your revs up, crisp can be obtained at a higher RPM it just won't be awake until you reach target RPM.

    So now were are getting into the real of personal preference, do you believe (I mean really believe) that high rev cruising is a rush? If that is so then stay with your current camshaft and match an intake to it. if you are not a true believer than get yourself a better street cam like an L-79 copy, with the short stroke motor it will give you a mild lope and be better off idle or close to it up through the 5200-5500 RPM range depending on your heads and cam shaft timming.

    OK I have said more than I should.

    happy motoring.
     
  19. mutant55
    Joined: Mar 11, 2012
    Posts: 174

    mutant55
    Member

    Well my two cents goes like this, as far as the carb goes, Q-jets are 750 cfm, and they do not have the best reputation, and I cannot figure out why, when is the last time you saw a 70 year old lady out with her hood up adjusting her carb on her original owner 70 Impala?? I use them on my Super Stocker too, they will supply enough fuel to run a motor that can put a 3400 lb car down the quarter mile in 9.80 seconds, so I am a huge fan of these carbs, and they made a few million of them.

    Manifold wise, I am with Engine Pro 5X, it's hard to beat a Weiand Stealth, but do not be afraid of a single plane edelbrock either, but the Stealth gets my #1 Vote.

    As far as the cam goes, something that has a 220-230 duration @ .050 and a maxlift of .480 -.520 is just perfect for that nice cackle at idle, but you could still run an automatic with a stock converter. Just my two cents.
     
  20. To me - my definition of " crisp street engine" is the tachometer needle acts like its attached to you foot.
    The low end off a stop light is right there pushing on the seat of your pants.
    It cruises with nice manners , gets decent mileage, and all hell breaks loose when you mash the throttle into passing gear. Authorative idle but not exactly lopey, decent vacuum.
    High average tq and HP from 1500-4500 rpm

    That's how I'd define it.
     
  21. What? nobody has heard of a 450 CFM Holley, great response, good mileage on a smaller engine......
     
  22. kennkat
    Joined: Aug 25, 2011
    Posts: 1,384

    kennkat
    Member

    I own 2 of them.. Great on a STOCK 283 or smaller motor, Not Enough on any 327, especially not a "291" headed motor with flat top pistons and a GK cam. That's my opinion after 38 years at this, plus the daily experience of Driving a 450 Holley on a 283 every day for the past 4 years...:):):)
     
  23. Kennkat, you are a youngin.....I have been doing carbs for 46 years.....
     
  24. 55 gasser pickup
    Joined: Dec 17, 2010
    Posts: 479

    55 gasser pickup
    Member
    from utah

    sp2p=small port dual plane.According to vicks web site.small prot dual LAME according to me;)
     
  25. fleet-master
    Joined: Sep 29, 2010
    Posts: 1,765

    fleet-master
    Member

    ok ....so the sp2p is now a paper weight....
     
  26. fleet-master
    Joined: Sep 29, 2010
    Posts: 1,765

    fleet-master
    Member

    Heres the specs I could find on the cam ..

    Ex open 79deg BBDC close 35deg ATDC ; Int open 30deg BTDC close 74deg ABDC

    112deg Ex to In , lift 0.430Int , 0.448 Ex , duration 284deg In ; 294deg Ex

    I've heard good things about Q-jets in the past and theres a few guys here who love 'em...so Weiand Stealth with a Q-jet?
    My heads need reco'ed ...is it worthwhile going to the 2.02" / 1.6" valves?
     
  27. Larry T
    Joined: Nov 24, 2004
    Posts: 7,675

    Larry T
    Member

    If you are going to run a Quadrajet (good carb), you'd probably be better off getting an intake made for a spreadbore carb and not use an adaptor. Some of the Stealths are, some aren't.
     
  28. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,331

    sunbeam
    Member

    The sp2p was Edelbrock answer to tha arab oil embargo when gas went to 45 cents. It has a small port to improve low end torque and mileage not preformance.
     
  29. If you are going with a Q-jet look for a Weiand 8004 intake. The specs on this cam still lead to it not having alot of bottom end and if it were used it would need to be advanced in the engine. The bigger exhaust valves would help also as a Chevy takes more in than it can exhaust >>>>.
     
  30. 68vette
    Joined: Jul 28, 2009
    Posts: 306

    68vette

    You helped me once big time on fixing my warped fleetline hood...

    I have a 327-350HP in my vette, it has a quadrajet with stock manifold, 3.55 rear, M21 4 speed trans with posi. It runs pretty good.

    I am very happy with the quadrajet, it sounds good, runs good, gets good milage, has not been touched since 1984...so, that is my suggestion to you.

    https://www.youtube.com/watch?v=TgBFh7m_45w
     

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