327 build...what to do?

Discussion in 'Engine Topic' started by TommyShameless, Oct 5, 2016.

  1. TommyShameless

    TommyShameless New Member

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    I am so glad you brought that up, since the heads I was looking at have 195cc runners!

    You just helped me avoid a big mistake!
     
  2. Highlife

    Highlife Veteran Member

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    I ran 327's for decades. Sadly fatkid is right about the small journal motors. The connecting rod bolts are only 11/32" and those Manley/TRW forged pistons weigh about 1.32 pounds each. That's a lot of weight to suspend on those tiny rod bolts at speed. Back in my day that's all we could get. We'd take an endmill chocked in the Bridgeport mill and put the slugs on a diet the best we could, but even then the skirts proved to be the weak link. By the time we got the rods to stay in the block the balancers would go flying, and friend I'll tell you a balancer flying off at 5500-6k rpm makes an eerie sound and destroys everything in its path. Which lead to us drilling and tapping or putting thread inserts into the crank snout, by the time we paid the local machine shop to do all that we could have built a 350. I'd sale that motor to an old codger like myself that has fond memories of high winding mouse motors.
     
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  3. fatkid_racing

    fatkid_racing Veteran Member Lifetime Gold Member

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    Sound advice from an old head that knows his 327's
     
  4. BUSHY 409

    BUSHY 409 Veteran Member

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    I HAVE 3 400 PONTICE AND A STD BORE 71 SBC [350] OUT OF A SS UP TO SOME HOURSE TRADING ,, WERE DO YOU LIVE? PS FATKID IS RIGHT THINGS GIT TO TURNING FAST BROKE A WATER PUMP SHAFT well you know the rest of the story !
     
    Last edited: Oct 13, 2016
  5. hogg

    hogg Veteran Member

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    Could you put the 305 crank,rods ,pistons in the .030 over 327 and have a .030 over 350.
     
  6. fatkid_racing

    fatkid_racing Veteran Member Lifetime Gold Member

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    That's all fine and good in theory, but contrary to popular belief the 305 crank has different counterweights than a 350 and requires quite a bit of time and several large/expensive chunks of mallory.
     
  7. rockheadrocks

    rockheadrocks Veteran Member

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    Seems to me there are really two choices here:
    - build the engine for the car
    - build the car for the engine

    The first option is generally the least costly. That being said, I'll toss in my two cents.

    The small journal 327 most definitely has some weak points as mentioned above. But let's face it, a street engine isn't going to see that max effort 7,000 plus rpm all that often, so I'd say the rods should be okay under "normal" high perf street use.

    If those pistons give a true measured 11.5-12.5 to 1, going from a 64cc to a 76cc head will only knock it down approximately one point. 93 octane would be greatly preferable. Aluminum heads get you a little safety margin.

    So here's what I would do:
    Promaxx 72cc chamber 185cc intake heads: http://www.jegs.com/i/ProMaxx-Performance/723/2171/10002/-1
    I would choose these along with a thicker head gasket as you mentioned because keeping the port velocity up is going to be pretty important for that 327. Compression is still going to be a little high, so be very careful with the ignition timing.

    As odd as it may sound, I have grown very fond of the VERY old school GM "151" grind cam, originally installed in L79 327's. However, it's more than a little long in the tooth, so I'd get this, Comp's more modern take on the L79: http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=110

    Moving to the intake, while the 2101 Performer you have would be just fine, it runs out of breath way before even this mild 327 combo wants. I would go to the Edelbrock 7104 Performer RPM Q-Jet manifold, since you already have the Q-Jet. And yeah, I hate Holleys. Q-Jet 4 Life. Those little primaries will be quite happy on the street, and the kick from those secondaries always puts a smile on my face. Because of the high compression, I'd let it run a tad rich.

    This engine "might" put out a true 350 horsepower, which would still put it miles above the stock 305 2bbl. You might enjoy it just fine as is without changing out the 3.08 rears. Don't lug it though. Low rpm plus high torque loads plus teeny weeny rod bolts=scattered bottom end. But if you think it's still too soggy at the bottom, try 3.42 before going much higher numerically. If you're still nervous about the bottom end, keep it under 5,750 or so and it could live a very long time.

    The best part: if you get tired of the 327, or the bottom end suddenly decides to leave the block some day, everything here will work perfectly on a 350.

    A final note: although the 305 and 307 are definitely the red headed stepchildren of the small block chevy world, either engine can be made to put a smile on your face. Sometimes you have to work with what you've got. They won't make the same power as a 327 or 350, but they will work.
     
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  8. TommyShameless

    TommyShameless New Member

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    Hi Bushy, I'm in New York. Brooklyn, to be exact, but the car and that engine are all kept safe out on Long Island. Whereabouts are you?
     
  9. mark wagner

    mark wagner Veteran Member

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    that's what I was thinking. if you think the cam might be too radical go for a 30/30 or Z/28 cam. if you want a juice cam, Comp makes a hydraulic version of the Z/28 cam (Nostalgia line). which in my opinion should work well with those pistons and later heads.
     
  10. Kamikaze

    Kamikaze Veteran Member Lifetime Gold Member

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    Okay, Here's my spin...

    Being that I used to build a lot of super budget motors with junk parts for people with no money, I have a few points to keep in mind

    327's a known more for their ability to rev up quickly and have higher rpm power. That being said, they were limited on low end torque and being in a heavy 2nd gen bird with lazy 3.08 gears, you will be limited on what you can do.

    Assuming you don't have to worry about smog equipment, you can have some fun...

    So, if you were to keep the existing block and high compression pistons, I would suggest you look for a nice 72cc head with smaller runners, (under 195cc's), and use a Fel Pro composition gasket 0.038". This will help reduce the compression ratio and allow you to have good intake velocity. If you are on a super tight budget and have to work with used OEM heads, the best you could find would be mildly ported 041 or 993 castings.

    If you have money to work with, then go for aftermarket heads like Edelbrock Performer, AFR's or EQ Torkers. Keep in mind you need to have heads with the accessory bolt holes on the end to attach all the accessories.

    By All means, get a hydraulic roller if you can afford it but if not, keep the lift and duration on the smaller side to build up torque. You probably won't need lift in excess of .488 and duration less than 230 degrees.

    Get a nice taller dual plane intake like a EPS, RPM Air Gap, Weiand Stealth, or stay with the Edelbrock Performer.

    Dial in a good distributor with a smoother and slightly quicker advance and you should have decent acceleration without much detonation as long as you keep the octane up.

    Keep the exhaust on the smaller side, 1-5/8" primary tubes and no more than 2-1/2" exhaust all the way back. And don't forget to include a crossover pipe!.

    If your budget allows more, than everything changes and I would suggest changing the rear end gears as others have stated to 3.73's to start. Depending on what you have available, then you can look at building the engine from there.
     

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