Clutch Question

Discussion in 'Transmission & Driveline Topics' started by Rayden2009, May 2, 2019.

  1. Rayden2009

    Rayden2009 Veteran Member Gold Member

    Messages:
    111
    Likes Received:
    14
    Joined:
    May 12, 2016
    Location:
    Calgary AB
    This may be a dumb question, but can I slap a 11” clutch into my stock system without a new bell housing and flywheel? I'm just getting into the research of replacing my clutch. I have an 80 z28 with a super T-10. Im pretty sure stock clutch is 10.5”. Do they interchange or should I stick with a 10.5” to avoid project cost runaway etc?
    Sorry if this has been covered before, I couldn't find anything relevant.
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

    Messages:
    22,491
    Likes Received:
    779
    Joined:
    Apr 14, 1999
    Location:
    Bismarck, North Dakota
    If the car came with the 10.4" clutch, you can't simply put in a 11" one in its place. The bell housing is different and will be too small. If you have the larger bell housing, then an 11" clutch and flywheel will fit.
     
  3. kenny77

    kenny77 Veteran Member Lifetime Gold Member

    Messages:
    2,693
    Likes Received:
    11
    Joined:
    Jul 31, 2001
    Location:
    Ft. Lauderdale, FL
    If your car has a dual drilled flywheel, then the bell housing is large enough 11 inch clutch and pressure plate will fit.
     
  4. 1978 Z/28

    1978 Z/28 Veteran Member Gold Member

    Messages:
    104
    Likes Received:
    24
    Joined:
    Jul 17, 2017
    Location:
    New Brunswick
    In 78 all Z/28s came with a 11 inch clutch. bell housing is the same for 10.4 and 11 inch clutch, starter nose is different
     
  5. Fbird

    Fbird Veteran Member Lifetime Gold Member

    Messages:
    3,948
    Likes Received:
    618
    Joined:
    Feb 12, 2011
    Location:
    atlanta, ga
    why add more mass...just get a good 10.4 clutch...unless you are really hooking up the rearend (unlikely) all an 11" clutch will do for you is add rotational weight (yes you might get a couple lb's of free torque due to the extra MASS) but certainly neither gain/loss is worth changing flywheel (if needed), starter (if new flywheel) bellhousing ....xxxxx IF NEEDED....now if you have a dual pattern flywheel ...sure get whatever you like...costs the same
     
  6. 1978 Z/28

    1978 Z/28 Veteran Member Gold Member

    Messages:
    104
    Likes Received:
    24
    Joined:
    Jul 17, 2017
    Location:
    New Brunswick
    I am going to use a L88 nodular iron flywheel weighs 15 pounds bought it new in 1980. Went to install starter block did not have inline holes.
     
  7. DesmoEd

    DesmoEd Veteran Member

    Messages:
    1,138
    Likes Received:
    7
    Joined:
    Sep 9, 2009
    Location:
    Frisco, TX
    I'm using the 15 lb GM L-88 flywheel in my '69 vette with a Hays 10.4 in street/strip clutch.

    Its a real hoot to drive as it engine brakes like a banshee making the on/off throttle transitions a blast coupled with the right tranny/gearing. My car is about 2800 lbs and I have 3:73 out back with a 2.87 1st gear close ratio road race 5 speed (TKO600RR).

    I'd caution against running it in a 3500 lb car with average gearing
     
  8. C4Racer

    C4Racer Veteran Member

    Messages:
    642
    Likes Received:
    112
    Joined:
    Oct 26, 2018
    15lb is very aggressive in a Camaro. It’s a heavy car. I just installed a T56 behind a 520hp carb 406 with a healthy cam and big carb and used a 25lb Ram billet Steel. Standard weight for a small block is 31-34lbs. I wouldn’t go under 20 unless you have very low gears and a pretty mild cam or EFI.

    I did run a 15lb in a C4 but that was a 3000lb car and had a mild solid roller with efi and I ran lots of part throttle timing off idle plus it had 4.30 gears.

    My rear now is only a 3.42 and it’s not ideal with the big cam. I was planning to go 3.70 but more likely will bump up to a 3.89 gear for better drive ability. It’s not bad now but you have to give it some slip off the line for sure. Especially when the motor is a bit cold. Better once warmed up. And I’m running a 1200rpm idle too.
     
  9. badazz81z28

    badazz81z28 Veteran Member

    Messages:
    16,697
    Likes Received:
    463
    Joined:
    May 4, 2001
    Location:
    Las Vegas, NV
    18lb is not too uncommon for an LS
     
  10. C4Racer

    C4Racer Veteran Member

    Messages:
    642
    Likes Received:
    112
    Joined:
    Oct 26, 2018
    Sure - I’ve run 15 on a EFI C4 too.
    But OP doesn’t have a LS or if so that wasn’t made clear.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.