Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

optional gear ratio 1ZN8 for 1973 What is it?????

Discussion in 'The Garage' started by ratchetmaster, Sep 16, 2003.

  1. ratchetmaster

    ratchetmaster Registered Member

    Joined:
    Mar 26, 2003
    Posts:
    47
    Likes Received:
    0
    Location:
    PLEASANT GROVE, UTAH U.S.A.
    I found a 73 chevy with this optional gear ratio listed. Does anyone know what it is??

    There was also a tag on the rear end (can't get to it to read) which I think indicates a limited slip diff. I believe this is a corporate 14 bolt.

    Anywhere I can go to find this info??
    Thanks
    Tim
     
  2. Shaggy

    Shaggy 3/4 ton status

    Joined:
    Dec 15, 2000
    Posts:
    6,737
    Likes Received:
    0
    Location:
    Los Banos, CA
    That doesn't look like a normal RPO code to me.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    GM threw numbers in front of some of the codes some years. The "standard" RPO code would be "ZN8".

    In any case, I can't find reference to that online. Parts manual for a truck might list it.
     
  4. ratchetmaster

    ratchetmaster Registered Member

    Joined:
    Mar 26, 2003
    Posts:
    47
    Likes Received:
    0
    Location:
    PLEASANT GROVE, UTAH U.S.A.
    Hmmm . . . it lists this on the tag located on the drivers side inner fenderwell. I am pretty sure I copied it down correctly.

    Would you all agree that if it has the tag on one of the bolts on the cover that it would be a limited slip diff??
     
  5. Emmettology 101

    Emmettology 101 3/4 ton status

    Joined:
    May 9, 2000
    Posts:
    8,126
    Likes Received:
    0
    Location:
    FL
    No, almost all rearends that came off the assembly line from GM had tags on them that usually listed gear ratio.... Not sure what other info was on the tag...
     
  6. avgas

    avgas 1/2 ton status

    Joined:
    Jun 5, 2003
    Posts:
    179
    Likes Received:
    0
    Location:
    Renton, WA
    You have 3.73 gears most likely. I have a 73 with the same code. I couldn't find most of the RPO codes listed on the truck much less the "1ZN8" listed anywhere on the internet. But I serviced my diffs last month and found "41-11" stamped on the ring gear, which is 3.73's. About the limited slip: you should have a seperate RPO listed with a description of posi-traction or something to that effect.

    Hope this helps
    Jake
     
  7. ratchetmaster

    ratchetmaster Registered Member

    Joined:
    Mar 26, 2003
    Posts:
    47
    Likes Received:
    0
    Location:
    PLEASANT GROVE, UTAH U.S.A.
    Thanks for the help!!
    I will try to get a better look at it and see what it says.

    One problem is the car is on the ground without tires (local yard) so I can't get to the tag. /forums/images/graemlins/frown.gif

    on cars, the tag always means posi. Not so on trucks I guess. I am still learning about truck stuff.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    All the car tags I'm aware of, SAY "Posi-traction" or "Limited Slip Differential" on them.

    Not sure of the trucks, never run across a tag on one myself.
     

Share This Page