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stock 327 heads on 350?

Discussion in 'The Garage' started by Cornfield creations, Nov 6, 2005.

  1. Cornfield creations

    Cornfield creations 1/2 ton status

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    I have a set of heads off of a 327 250 horse engine, they are not the double hump heads. Right now I am planning my engine rebuild for my k-5, right now it is a stock never rebuilt engine. What I am going for is reliability, good torque through-out the RPM range and trying to do it the cheapest way.

    What I was wondering is if I decide not the do the bottom end would a set of 327 with a smaller chamber, and I am assuming low beck height work? I believe the 327 was a 10.5:1 ratio. Also I was wanting to make it full roller valvetrain with a performer air gap intake, maybe keeping the stock q-jet as it works great, but maybe upgrading to a 650 holley.

    Any suggestions?
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Start with a roller block if you want to go that route, if you don't already have one.

    The gains from a roller setup are NOT worth the $1000 or so dollars that they cost IMO, and the cost of a core roller motor is going to be small enough that you will still come out ahead. Used cams are no problem, and you can find stock roller cams on ebay for pretty cheap.

    What CC are the heads you've got now? The 327 heads are what, 58CC's, (my mistake, was thinking 283) and stock truck 350 heads our vintage are 72CC IIRC.
     
    Last edited: Nov 6, 2005
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    327 heads came in either 62cc or 64cc combustion chambers and most other GM 350's are 76cc chambers. 327 heads do not have accessory bolt holes on the ends and the early heads did not even have a temp sender hole in the side of the heads, the sender hole came in about 1968 just after the 350 was introduced.
     
  4. 78Suburban

    78Suburban 1/2 ton status

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    could you just run a manifold with a temp sender on it?
     
  5. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Yes you could or just drill and tap a sender hole into the side of the head. On the later 327 heads just before GM put a sender there they started to cast a machined surface where a sender hole would be.
     
  6. Cornfield creations

    Cornfield creations 1/2 ton status

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    I know in 63 they had only those two heads on the 327. They're not the double hump which were 64cc, so I assume they are 62cc. The engine I pulled them off of to put in my Impala SS I made it full roller, but I went through a push rod already with only 2000 miles so I was kinda worried about reliability on the roller cam. I will hold off on the roller setup for now, I am gonna be collecting parts here and there to do it this winter.

    Those heads I have will need to be rebuilt, they need new valves and everything so I guess I should ask, would they be worth it to redo and put on my 350, or would I be better off rebuilding my heads on my 350?
    I don't wanna pay $500 for a set of heads, but I don't wanna stick a ton of money into heads that are worthless and won't do anything to enhance the output of my engine. It's my DD and will be using to towing and other things.

    My engine only has 86,000 miles, should I go through the bottom end or would it be good to let it go. I babied this thing and I have always run synthetic in it.
     
  7. 3 on the tree

    3 on the tree 1/2 ton status

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    If you want to use the 327 heads, hardened valve seats will have to be installed to run unleaded gas ($$$$$). I would stick with the orig heads for that reason alone.
     
  8. Cornfield creations

    Cornfield creations 1/2 ton status

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    Oh yeah I totally forgot about that!
     
  9. Cornfield creations

    Cornfield creations 1/2 ton status

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    Oh yeah I totally forgot about that!

    Does anyone have a writeup on a good 350 build? I know sometimes in magazines they should what they do and what they get out of their engine, like a budget buildup.
     
  10. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Hardened valve seats for unleaded fuel is a BS story. You will wear out valve guides long before you wear out a valve seat because of unleaded gas.
     
  11. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

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    im not sure on the 327 heads but i know on the 305 heads, if you put those on a 350 you will bump up compression another 1:1, creating a 10:1 ratio. if the 327 heads are the same, just bigger or what ever compared to 305, i dont see why they wouldnt work.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    You'll probably need to price out all the parts to re-do those heads, so your looking at valves, springs, valve job, perhaps some stud pinning or replacement, and all the related machining that goes along with re-doing heads. I probably missed some stuff, but I'd think that would run $2-300? Around here $300 gets you a set of heads redone from what I recall.

    I guess they probably aren't worthless heads, but compared to whats out there, much better options exist, especially when looking for power in something you will want to enjoy everyday.

    As with everything, depends on how much you are willing to spend.
     
  13. 3 on the tree

    3 on the tree 1/2 ton status

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    I am running unleaded in my OE 70, only because there is enough lead build up on the seats to protect them. If the hardened seats are not necessary, why do the manufacturers use them. We all know how much GM likes to spend money on unnecessary engine parts. Gm also puts oil filters on their engines. The engine will run fine without one, just not as long.
     
  14. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    GM DOES NOT use hardened seats in SBC engines.

    If you want to know what happens because of unleaded fuel PM me and i will tell you the difference between leaded and unleaded fuel.
     
  15. 3 on the tree

    3 on the tree 1/2 ton status

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    OK, maaybe I'm a dumass, but when GM went to unleaded engines in the 70s, I KNOW they used hardened seats in the beginning. Those 327 heads would fall in the same category as early unleaded 350 heads. I guess we should define "hardened". That does not always mean a seperate seat, it could be a heat induction hardened seat also. Anyhow, if I waanted to use those 327 heads, I would ask around a bunch of different machine shops their opinions before I started putting money into those heads.
     

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