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Technical Early Pontiac V8 Interchangeabile parts question

Discussion in 'The Hokey Ass Message Board' started by semaj4712, Sep 22, 2018.

  1. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    Hey everyone, I have a 55 2nd GMC with a stock Pontiac 316 in her that is pretty tired, no longer has acceptable compression and burns oil possibly more than fuel.

    So I am going to pull it and give it a good rebuild, but while I am at it, I want to do some upgrades to give it a little more go.

    From what I understand the 316 is essentially the same block within reason as the 347, 370, and 389 (59-60 Only)but really all that is different is the stroke / bore. Again this is from some pretty simple research and may not really be true.

    So what I am wondering is, can I take some mild or basic alluminum heads from a 389 and bolt them on with minimum modification?

    I would like to essentially bore the motor out a little bit, clean it all up. Throw in a 347 or a 389 crank, new rods and pistons, A mild cam, Alluminum heads, Performer RPM intake, 4 Barrel Carb, headers and call it a day. (along with all the normal maintance things, like timing chain, water pump, oil pump etc.)

    Would this work or am I completely confused.
     
    chryslerfan55 likes this.
  2. You will be money and time ahead to find a 59 or 60 389. Later heads aint gonna work with the reverse cooling you now have.
     
    chryslerfan55 likes this.
  3. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    I thought the 59 also had the reverse cooling? Or is the problem that all aftermarket heads are not going to work with reverse cooling regardless?
     
  4. My Pontiac experience is mainly with 65 and later engines and limited experience on 61-64 engines. None on 60 and earlier though.

    I'm not familiar with anyone making an Aluminum head for a pre-65 engine, while they would bolt to the block the intake pattern and design is different so the whole upper end package would have to be replaced. Using the 65 and later heads on the 60 and earlier engines would also have to have the timing cover replaced also if memory serves me correctly due to the coolant flow path.
     
    chryslerfan55 likes this.

  5. Look at your heads. See the water necks attached to the front of the heads? The newer engines don't have them.
     
    chryslerfan55 likes this.
  6. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    I see what your saying. But essentially I could run 59 389 heads and take advantage of the better flow, just not modern aftermarket heads then.
     
  7. Poncho60
    Joined: Jan 23, 2011
    Posts: 237

    Poncho60
    Member
    from N Illinois

    The main journals on the 56 316 are smaller than the mains on the 57/58 347/370 which in turn are smaller than the mains on the 59/60 389's. If the engine in your GMC is the original would it actually be the 55 287? The 316 was a 56 engine.
     
  8. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    I just found that on another site, seems like my rebuild will essentially be a stock rebuild nothing crazy, which is okay too.

    GMC 55 2nds had the 316 as the upgrade option. Technically a 56 motor, but it was available in a small amount of the 55 2nd GMCs as the V8 Upgrade.
     
  9. carbking
    Joined: Dec 20, 2008
    Posts: 2,914

    carbking
    Member

    There are some performance upgrades.

    Get a copy of Pete McCarthy's book "Pontiac Performance - 1955 to 1979"

    Absolutely required reading if you are planning working on a Pontiac V-8. And it is in paperback format, so it won't break the bank.

    Jon.
     
  10. OLDSMAN
    Joined: Jul 20, 2006
    Posts: 2,423

    OLDSMAN
    BANNED

    Why not replace that 316 with a later 389 or 400 that you can get performance parts for? That would seem the best to me.
     
    Stude350guy likes this.
  11. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    I will have to check that out, thanks!

    I may, 60 would be the only year I would really be interested in since it has convetional cooling so I could run newer heads, and it still has the same mounts as my 316 so no fabrication to get it in there. Which is important to me, I don't wanna hack anything up.
     
  12. ClassicDriver
    Joined: Mar 8, 2010
    Posts: 115

    ClassicDriver
    Member

  13. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    Oh wow thanks for that!
     
  14. ClassicDriver
    Joined: Mar 8, 2010
    Posts: 115

    ClassicDriver
    Member

    It will take a lot of time to read that stuff, but well worth it.
     
    Brantech likes this.
  15. Anything newer than a 60 -389 will not bolt up to your early transmission.
     
  16. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    The first post is probably the best,

    This is what I am thinking, either rebuild what I have as essntially a stock rebuild.

    Or...

    Find a 1960 389, that should bolt right into my truck, and to my rebuilt Hydramatic 4 Speed no problem.

    Mild Cam (Ponchos like more lift and duration on the exhaust side)
    Must be drilled to provide oil via #2 and #4 cam journals

    HEI Igniton from 75-81

    I already have a spare spin on oil filter adapter, and Hedman D Port Headers.

    Hollow Pushrods to make sure I can use after market heads If I decide to.

    New Rods, New Pistons. Pistons will have to match the head, the valve angle changed in 65 so I need to make sure the heads and pistons match.

    Might try to pick something up from Butler but we'll see, I may also just run the stock 389 heads.

    If I decide to go stroker, Butler has a 4.25 fast crank for sub $300, might be worth it since Im already doing new rods and pistons.
     
  17. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    Also be curious on thoughts in regards to getting the stock 389 heads off of the 60 motor ported and running that instead of after market heads.
     
  18. semaj4712
    Joined: May 28, 2013
    Posts: 98

    semaj4712
    Member

    I just got the book in the mail and after a quick reading, I am not savy on a bunch of random pontiac knowledge. In all honesty I am not sure what I learned but it all seems like a mismash of random information.

    I don't think it really changes anything in regards to what I want to do as I posted a few posts ago.

    The 316 is going to probably cost more to rebuild just to stock let alone a light performance build, simply do to parts availabilities for a 1 year motor.

    So I think the 60 389 is the way to go, again with a mild cam, new rods and pistons.

    Probably stock crank just cleaned up, but a stroker crank is still probably too cheap to pass up.

    Then for the head, this is probably where I am the most unsure.

    It sounds like the stock heads are pretty good, and could work with little modification, and it appears based on the book that their 63-66 are prolly the better heads given valve size but hear to tell. It does not talk about changes to intake volumes or anything like that which I had hoped it would. But, I think if I wanted to run stock heads and keep the stock pistons or the like, that I could go with a 421 head pre 65 and get a little better flow, may not even be worth the effort tho.

    Any recomondations on heads would be really great, preferably given two situations, stock crack and mild cam which I would prolly just say then stock heads. But if I decided to do a stroker, 4.25 in stroke, then I would think higher flow heads would be required.
     
    chryslerfan55 likes this.
  19. Bird man
    Joined: Dec 28, 2009
    Posts: 594

    Bird man
    Member
    from Milwaukee

  20. The OP hasn't posted in a long time. I now have a 60 389. I bought a 60 C 60 pontiac 003.JPG atalina at a estate auction new years day.Gonna pull it and use a 56 GMC 316 bell and flywheel on it and install in a truck.
     
    chryslerfan55 likes this.

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