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Poly/Hemi Interchange questions...

Discussion in 'The Hokey Ass Message Board' started by chuckspeed, Dec 23, 2005.

  1. chuckspeed
    Joined: Sep 13, 2005
    Posts: 1,643

    chuckspeed
    Member

    Well, I did it.

    Inna moment of weakness, I bought another car - a '55 Chrysler (pix attached).

    The good news is it's a reasonably solid low miler; the bad news is it's a poly head 301. About 15 years ago, I had a '56 poly head Chrysler with the Power Package - dual point distrib, 4 barrel manifold, dual exhaust - and the big beastie ran out rather well. I'd like to hop up the motor a tad (along with some other things) and had a couple of questions:

    1) can the similar vintage hemi manifolds be adapted to fit the poly?
    2) ditto for headers - if the bolt pattern (2 center bolts on the poly vs 1 on the hemi) is modified - can the hemi headers be used?

    I know pretty much everything below the deck line is the same, so 331 hemi cams will work - got any suggestions on who is a good source for a hotter cam?
     

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  2. krooser
    Joined: Jul 25, 2004
    Posts: 4,585

    krooser
    Member

    Talk to George at Clay Smith cams in Buena Park....he's knowledgeable on Hemi's and will custom grind what you need... www.claysmithcams.com

    The website is pretty lame with more clothing than hardparts BUT you'll get what you need and it will be right...no surprises...
     
  3. J Man
    Joined: Dec 11, 2003
    Posts: 4,121

    J Man
    Member
    from Angola, IN

    I think you have to swap the heads out to run a HEMI intake and headers. Get a hold of Hyfire, he knows his stuff. Also there is a place called Hot Heads that does all HEMI stuff. They should have anything you want.
     
  4. chuckspeed
    Joined: Sep 13, 2005
    Posts: 1,643

    chuckspeed
    Member

    Nope - not swappin' the heads; wanna run what she brung.

    The '56 331 poly made 250 HP - same as the stocker 331 hemi a year earlier. damned thing went like stink. Was planning on digging up a McCulloch VS57 to get the little 301 up to snuff by force feeding it. Just wanted to get a 4 barrel topside; the hemi manifolds are plentiful where the power pack poly's gotta be hard to find!
     

  5. George
    Joined: Jan 1, 2005
    Posts: 7,336

    George
    Member

    the intakes interchange
     
  6. J Man
    Joined: Dec 11, 2003
    Posts: 4,121

    J Man
    Member
    from Angola, IN

    I have a '55 260 PLYMOUTH POLY THAT I bought a 3x2 Offy intake for. I got it off Vaphead for $225. He can probibly find one for that engine.

    Also get on www.forwardlook.com and see what you might be able to find.
     
  7. Yo Baby
    Joined: Jul 11, 2004
    Posts: 2,812

    Yo Baby
    Member

    "Was planning on digging up a McCulloch VS57 to get the little 301 up to snuff by force feeding it. Just wanted to get a 4 barrel topside; the hemi manifolds are plentiful where the power pack poly's gotta be hard to find".

    Do you have a Tex Smith book or know for certain whether or not the 270 and 301 have the same deck height?
    If the deck height is the same on both I have a freind I'm building a 270+ for that might have an intake.It would be nice to know for sure on the deck height because if they are the same it would be worth the trip over to see if not it wouldn't.He is partially deaf and does not talk on the phone.
    You are looking for a 4bbl factory cast one ,right?
    T.OUT
     
  8. chuckspeed
    Joined: Sep 13, 2005
    Posts: 1,643

    chuckspeed
    Member

    The 270 and the 301 have zip for interchageability.

    the 301 was a one-year-only engine which shares its basic architecture with the 331 hemi, 331 poly, 354 hemi and 354 poly. 95% certain the 270 has different bore spacing, which means the intake wouldn't fit.

    I'm at a crossroads when it comes to a build sheet on the motor. I like N/A motors; the cool factor would be a dual quad intake and a mildly lumpy cam. Problem is, a 301 would have to be spun pretty tight to make HP and a two ton windsor needs torque down low to move. Better pick is a blower huffin' a four pot carbie and an OEM CI intake - but it's not as pretty.

     
  9. ol fueler
    Joined: Oct 6, 2005
    Posts: 935

    ol fueler
    Member

    Get ahold of Chris Nielson in Utah. (801) 451 7745 . he is GREAT at regrinding early Chrysler Cams & most likely will have all the info you need to make any hop up or swaps .
     
  10. Yo Baby
    Joined: Jul 11, 2004
    Posts: 2,812

    Yo Baby
    Member

    Neilson not only re-grinds but is the only guy I know of who actually has new billets for the early hemi/poly.
    In any event if I had been more awake I would have realized you were talking about a Chrysler and not a Dodge and would have known better than to ask.LOL
    All the cores are dodge stuff.
    T.OUT
     
  11. Squablow
    Joined: Apr 26, 2005
    Posts: 14,646

    Squablow
    Member

    The car looks like a nice one, and I'm glad you're going to use the original motor. There was a guy on here a week or so ago who responded to the hotrod poly thread, but he got flamed pretty bad and I don't know if he'll be back. He said he had all kinds of speed parts and shit for sale to soup up the Mopar poly engines.

    And I agree that www.ForwardLook.net is a good place to look for parts AND ask questions, they seem to be the Poly gurus over there.

    I just bought a '55 Dodge last week. There must be a clearance sale on 50's Mopars.
     
  12. by the way, nice windsor.

    (thanks for the tech stuff too)
     
  13. chuckspeed
    Joined: Sep 13, 2005
    Posts: 1,643

    chuckspeed
    Member

    thanks, squab and fur! this will be my 2nd windsor; the first was a '56 with the power pack. I really liked that car.

    A while back I'd posted a WTB in the classifieds with the purchase criteria. Was poked a few times on how the critieria were unrealistic - but here I am a few weeks later with a solid low mile fitty five.

    The poly is a better motor for the street, IMHO. While they don't breathe as well topside - they do a MUCH nicer job of breathin' as compared to their contemporary engines, and the combustion chamber shape is more conducive to high compression than a hemi chamber is, and the port config is not unlike the hemi. The result is more area under the curve down low - where it counts on the street.

    Anyway - it doesn't hurt to huff up a poly. Same guts as the base hemi underneath. I figure I can squeeze 350 HP outta one pretty easy, and - if it blows, a replacement motor can be had on the cheap as no one wanted the poly to start with!

    Go figure.

    I'm just torn on the build. The 'right' thing to do is a blow-thru centrifugal supercharger, but the jaw drop appeal goes to dual quads. A little 301 won't like a pair of 500 cfm Carter AFB's, so the back carb's secondary would hafta be disabled. Seems a shame to run 75% of a dual quad setup; also seems to shame to build a high winder and stuff it inna two ton rig.

    The goal is to build a nice cruiser that can shove its two ton chromed snout under the ass end of them pesky fart-tipped R-type wingnuts just for the heckuvit.

    Kinda like the opposite of the beep beep song...
     
  14. Gary Pavlovich
    Joined: Dec 9, 2005
    Posts: 16

    Gary Pavlovich
    Member
    from CA

    Chuckspeed,

    Nice Chrysler Windsor! You are right that the Poly can run. If you obtain the dual quad intake you are talking about, you can run the WCFB carbs on the 301 as they are compatible with your cubic inches. You may even consider strokin' the 301 for more inches. I build the Poly 318's but the parts are not interchangeable with the Chrysler Poly.
    Keep me posted on your project and what you come up with.
    By the way, I can help you with a high performance cam grind if Clay Smith isn't able to help you.
    Take care,
    Gary Pavlovich
    402" Poly Stroker in my '56 Savoy
     
  15. chuckspeed
    Joined: Sep 13, 2005
    Posts: 1,643

    chuckspeed
    Member

    Thank you, Gary!

    I jave two build sheets going in my head at the moment - one for a blown motor and one for a dual quad motor. I'm leaning towards the dual quad motor simply for the jawdrop factor when parked alongside Woodward. If I wanna go fast - I've got a 12 sec daily driver.

    To make the WCFB's work well on the street, I was thinking about partitioning the manifold into quadrants and running a straight linkage as opposed to a progressive. That way, each primary venturi would 'see' a pair of cylinders. WCFB's are rated at 100 cfm/venturi, so they'd get a good signal. A couple of 2" spacer blocks would also help reduce transition turbulence.

    While I'm sorting all this out - it wouldn't hurt to be on the lookout for a 354 - and an A-488.


     
  16. Hyfire
    Joined: Jun 18, 2004
    Posts: 1,232

    Hyfire
    Member

    Sorry to bring this post back from the dead... It looks like you got your answers... Check out the "Poly Performance" booklet... I think it is published by Victory? It will tell you everything you need to know about performance and your motor... The guy also sells it on Ebay... Just about 50-100 pages stapled together, but well worth the cost...
    PM me if you have any questions....

    Best Regards,

    Hyfire
     
  17. Bugman
    Joined: Nov 17, 2001
    Posts: 3,483

    Bugman
    Member

    I second the Victory Library Poly Performance book. It's got tons of useful info in it.
     
  18. chuckspeed
    Joined: Sep 13, 2005
    Posts: 1,643

    chuckspeed
    Member

    Thanks for the suggestion on the poly book - I'll be sure to pick one up!

    Really like the tunnel ram intake that hot heads has - will consider that during the build.

    Question:

    I'm planning on doing a blog of the project. Is it better to run a thread here - or start a separate page and link to it?

    what do you think?
     
  19. geokid
    Joined: Oct 8, 2012
    Posts: 7

    geokid
    Member
    from florida

    i think you should just keep it here
     
  20. George
    Joined: Jan 1, 2005
    Posts: 7,336

    George
    Member

    This has been dead 8 years....
     

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