What size intake runners for a street bruiser 327?

Discussion in 'High Performance Modifications' started by slayer021175666, Mar 3, 2018.

  1. slayer021175666

    slayer021175666 Veteran Member

    Feb 29, 2016
    I'm about to buy some ATK heads. I was thinking about the 185cc heads for my 327 when I saw an Air Flow Research article where a guy got over 500Hp with thier 195cc heads. Now I don't know what to do. I've also been told my cam is too big. Its a Performer RPM cam.
    So, intake runner size and cam selection is what I'm wondering about.
    Any advice about the head choice or head and cam combo would be appreciated.
  2. dave@ztech

    dave@ztech Veteran Member Lifetime Gold Member

    Mar 27, 2016
    Didn't the guys that do the Engine Masters series , do a video regarding this exact topic, I can not remember, however, I know , that getting all of this correct will make a huge difference, good/bad, with the wrong choice , so I will be interested to see the answers as well?
  3. SRGN

    SRGN Veteran Member

    Feb 20, 2009
    Central NJ
    Put up the rest of the combo. If you're spending more time in higher RPMs the loss of port velocity at lower RPM with the 195s won't be as much of an issue.
  4. slayer021175666

    slayer021175666 Veteran Member

    Feb 29, 2016
    Mostly low and mid-range street stuff. Light to Light use. some 100 mile freeway trips.
    Currant Configuration
    Flat top pistons
    194 64cc Camel Humps Shaved .020 with steel shim gaskets
    1.5:1 Full roller rockers
    Performer RPM manifold (NON-AIRGAP)
    Eddy 600CFM manual choke carb
    1 5/8 long tube headers into 2.5 mandrel bent pipes ran clear out the back with flowmaster 40 series mufflers
    MSD 6A on HEI
    100 shot N2O
    Turbo 350 with 2500 Stall and Trango shift kit
    8.5 "POSI" rear with 3.08 gears (need to do something about that too but, can't decide on keeping the turbo 350 or buying a 200-4r or 700 r4.)
    Tell me if I left anything out.
  5. 1980RS

    1980RS Veteran Member

    Jun 17, 2006
    Here is a rule I always use when it comes to picking cyl. heads, always get the smallest runner that will do the best job for your engine, velocity is the key here. With that being said I have seen many times guys buying 195-210cc heads especially for street cars only to have poor results on smaller engines. This past year was no exception for me. I was highly doubtful of the Peanut Port heads I used on my 461 that were only 230CC for a big inch engine, but you know what? that darn engine made a ton of power and tq. and even at my age things still surprise me. If I were to run a 327 I would use exactly what you are thinking of using, 185CC heads, but for me I would get the 185 CC Vortec Bow Tie heads. They are just a tad bigger than 062's and we all well know how those work. Don't fall into the BIB (bigger is better) syndrome, let someone else do that. Same goes for camshafts.
  6. Lee45

    Lee45 Member

    May 28, 2017
    With a 600cfm carb and small intake I'm guessing you're gonna be sub 6k rpms with a decent cam so I also agree with something around 180cc, just get the best cylinder head you can afford. If you don't mind changing the intake, the edelbrock E-tec 170's are a pretty good bang for the buck, but some aftermarket iron vortecs in general would work perfect. Better to go too small than too large honestly.
  7. slayer021175666

    slayer021175666 Veteran Member

    Feb 29, 2016
    185cc is the smallest they sell. After giving it some thought, The 195s were measured for top end HP not, low end grunt. And, low end grunt is what I'm after so, the 185s would probably be the better choice.
  8. larrylarry

    larrylarry Veteran Member

    Dec 22, 2011
    San Antonio Tx
    Hell, I’m running iron GM Vortecs (ported) that are 172 cc on a
    medium hot 357 ci. SBC.
    750 Edelbrock carb
    Edelbrock Performer intake
    10.4 compression
    6” Rods
    1 5/8 headers
    Howard’s Cam 525/530 w/106 CL
    700r4 trans / 2800 stall TQ
    3.42 gears
    I’d say the 185 cc heads would work great. It does tend to run out of HP @ 5500 rpms but that’s fine with me. If you went to a 700 or 200r4 I’d strongly suggest you go with 3.90’s or 4.10 gears. That’s something I need to do mostly due to the overdrive trans.
    Last edited: Mar 4, 2018
  9. Mwilson

    Mwilson Veteran Member

    actually if you really want low end grunt why swap the camel humps? the measurable difference probably wont be much. I know they are old school but they work
    Lee45 likes this.
  10. Lee45

    Lee45 Member

    May 28, 2017
    I overlooked that you already had camel humps, and in that case as far as Low end goes, you're pretty much there, like @Mwilson said, swapping heads may not really do anything honestly but increase high rpm power. rpm Cam has a pretty broad band and changing it would have more of an effect in moving torque lower but not much. In all, what you have should be pretty stout as it is and I think you're asking for more than a 327 would give torque wise, its not a 383 or 400. Gears would do more than any cam or head swap. 3.08's and high acceleration don't go in the same sentence.
    Mwilson likes this.

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