Register now to get rid of these ads!

Technical Spark Plug Wires - Standard vs HEI

Discussion in 'The Hokey Ass Message Board' started by 64impala, Aug 5, 2016.

  1. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    I'm replacing my Mallory distributor cap and rotor (Old ones worn out) on a HEI ignition.
    When I received my new units, my old 8mm Taylor Pro Wire set don't seem to fit the new cap, its as if Mallory changed the specs to only fit or better fit there wire sets.
    So, it appears I'll have to purchase a new set of spark plug wires/coil wire.

    Question: Do I have to purchase a specific "HEI" wire set or will a "Standard" (non hei) set also work? What's the difference in the sets?

    Make: Chevorolet
    Year: 1965
    Model: Impala
    Engine: 327ci
    Ignition: Mallory HEI
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 47,769

    squirrel
    Member

    If you post some pictures of what you are working on, we can tell you better. The GM HEI distributors, which mostly showed up starting in 1975, use a male terminal, size and shape like the terminal on a spark plug. The older non-HEI distributor cap has female terminals. So, there's a big difference, and the HEI does take special wires.

    But I have no idea what your Mallory HEI thing is. Post a picture of yours, or the part number, or something
     
  3. oldsjoe
    Joined: May 2, 2011
    Posts: 2,530

    oldsjoe
    Member

    Here is a picture of a HEI style cap and a Points style cap. An Inny and an Outty if you will. The points style the wire end goes into the HEI style the (MSD) wire end goes over. You can just change the wire ends to whatever it is you need. Or order a Mallory cap with the correct style you need. I believe they are both still made. Joe

    images.jpg 41xsoXZxItL__AC_UL320_SR278,320_.jpg
     
    carolinakid likes this.
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 47,769

    squirrel
    Member

    Although MSD owns Mallory now, and Holley owns MSD, so who knows what you have...?????
     

  5. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    ok, this is what I'm running. The old Mallory parts are at least 15 years old, including the "Taylor" spark plug wires.

    The question was: Why doesn't the old sparkplug wire set fit the new Mallory Cap/Rotor?
    All I did was order new Mallory cap/rotor to replace the old, nothing has changed.
    I wondering if Mallory changed their cap specs so that I'm forced to use their wire sets!

    MALLORY PARTS:
    Distributor: 4748201 C.A.R.B. E.O: D-70-9
    Coil: 29440
    Optic Module Spike Filter: 29351
     

    Attached Files:

  6. squirrel
    Joined: Sep 23, 2004
    Posts: 47,769

    squirrel
    Member

    that should use a stock wire set, but who knows...maybe if you take a picture of the part you actually have in front of you, and are trying to get wires to fit, we could help?
     
    oldsjoe and saltflats like this.
  7. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    ok, here we go!

    Original cap and wire(s) on left, new cap on right.
    The old wires fit snug on the old cap, but are to loose on the new exact same cap!
    I'm guessing the best way to solve this is to take the new cap into a parts store, bust open a few
    spark plug wire sets and determine which fits properly.
    I presume I should stick to an "HEI" wire set, or is this not true?
    What's the big difference in a "Standard" and "HEI" set?
     

    Attached Files:

  8. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    From 2010 "Tech" article:

    "If you are running a bone stock car on the street as a daily commuter then the OEM carbon core wires are probably fine. Any upgrades in performance, especially in the fuel or ignition system would require Spiral type wires. Solid core wires will work fine for carbureted race car with condenser points or magneto type ignition systems."
     
  9. squirrel
    Joined: Sep 23, 2004
    Posts: 47,769

    squirrel
    Member

    That cap does NOT take HEI wires.

    fwiw, I have an old Mallory dual point dist that uses that cap, and I have the cheapest, most generic stock replacement plug wires for a 66 Chevy 427. On the blown 427 in my 9 second car. I guess I don't' read the right ads? :)
     
    oldsjoe, BobMcD and saltflats like this.
  10. saltflats
    Joined: Aug 14, 2007
    Posts: 10,544

    saltflats
    Member
    from Missouri

    Okay did you not say you changed caps?
    I don't see the difference.
    You have to pull the boot back then engage the wire end and slip the boot down to it.
     
  11. saltflats
    Joined: Aug 14, 2007
    Posts: 10,544

    saltflats
    Member
    from Missouri

    Now why would you want anything else.
     
  12. upspirate
    Joined: Apr 15, 2012
    Posts: 2,261

    upspirate
    Member

    Can you reach into the boot and spread the little prong to make the wires fit tighter? The holes maybe larger as they use larger diameter wires now days (8MM instead of 7 MM I think):confused:
     
  13. upspirate
    Joined: Apr 15, 2012
    Posts: 2,261

    upspirate
    Member

    I know when I changed my wires and looms, the looms were loose on the old style smaller wires
     
  14. oldsjoe
    Joined: May 2, 2011
    Posts: 2,530

    oldsjoe
    Member

    Those caps look the same to me. Do as upspirate suggests. Or are you saying the boot is too large or small? Joe
     
  15. [​IMG]

    With so much stuff not being made at the original factory anymore. Is it any wonder ? I see it even without using one of these..... [​IMG]
     
  16. greybeard360
    Joined: Feb 28, 2008
    Posts: 1,593

    greybeard360
    Member

    The distributor you have is a Unilite.... Not an HEI

    Should accept standard wires. Measure the diameter of the towers. You might answer your question if the new ones are smaller in diameter.

    Sent from my LG-H343 using The H.A.M.B. mobile app
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.