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K30 w/hydroboost clutch pedal solution

Discussion in 'Manual Transmission & Clutch' started by Frankenchevy, Oct 18, 2020.

  1. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier

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    I think I have it pretty well sorted at this point. I’d just like to confirm:

    -Since 1-piece rear main seals began in 1986, is the flywheel from a 1987 5.7 compatible with my 96-99 vortec 350?

    The Advance Adapters bellhousing pn 712576 is designed to be dimensionally the same as an 85-87 sm465, therefore allowing guys to run stock components from those vehicles, such as external slave cylinder, clutch, etc.

    I’d just like to confirm that a flywheel from an 87 k30 5.7 sm465 truck will in fact work on my vortec 350.

    Thanks for the help!
     
  2. bucket

    bucket Super Moderator Staff Member

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    Yep, same one.
     
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  3. bucket

    bucket Super Moderator Staff Member

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    To clarify, the same flywheel was used on the Vortec 350 too. At least with the nv3500. The 4500 maybe used one with a bigger clutch?
     
  4. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier

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    They both seem to be 11-1/2 or just a tad smaller than the flywheel diameter. When searching RA for a 97 3500 5.7 manual trans I get this:

    2BBE80FB-EB5F-4A0E-B300-8F4EB5D45794.png 7560FEFC-84C7-47AF-929B-ECD3E4A6EF08.png
     
  5. Dutch Rutter

    Dutch Rutter Full Access Member

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    For pedals I think this is the setup your wanting to get. I picked these up for $250 on the ebay a while back, along with a steering column from a manual trans truck. Now they are just sitting in the garage and waiting.

    20201021_211452.jpg
     
  6. SquareRoot

    SquareRoot Full Access Member

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    Bingo! I've also got a set waiting for install and a set for vacuum brakes. There are slight differences between the two in the mounting configuration to the firewall.
     
  7. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier

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    Yeah, I’ve pretty much come to the realization that since the set I have coming aren’t for hydro clutch and hydro boost brakes—I’ll have to build my own bracket and clutch pedal. I’ll leave the brake pedal assembly alone and probably cut the pedal pad plate down to fit a narrower pad. I’d rather leave the bulk of that assembly alone. I can deal with the clutch going awry whilst driving, the brakes failing is another thing.

    Shouldn’t be too difficult, just melting some metal.
     
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  8. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier

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    Well, my incorrect pedal assembly came. It feels really solid. Shame it’s the wrong one.
    EBF34F89-12F3-44DB-AB0B-F9850A415F5C.jpeg
     
  9. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier

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    Anyone in internet land have an nv4500 np208 combo? I’d like to see how close the floor holes for the shifters are to each other.
     
  10. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier

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    @bucket

    the person selling these claim they’re from an 85 c20 hydroboost truck. Doesn’t seem correct to me. Doesn’t the hydroboost mounting flange have only two studs from the cab side and two bolts from the engine bay side? This one has all four studs from the interior side as seen below...
    13D1E941-0786-46FE-BD97-D5D439A4FBB8.png 1504D349-1AC7-4F3C-B9D1-DA44C05D0536.png
     
  11. bucket

    bucket Super Moderator Staff Member

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    I can never remember for sure. But I think the hydro pedal bracket is the one with 4 studs.
     
  12. SquareRoot

    SquareRoot Full Access Member

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    Hydro boost has 2 studs like this. I have all four versions of pedal assemblies (85-87) sitting in my garage.

    IMG_20201026_125700662_copy_1600x1200.jpg
     
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  13. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier

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    You want to sell a hydroboost/hydraulic clutch assembly from an 85-87 to me?

    that one in your pic looks right — with the two stud hydro flange. In the pic it looks like it only has the one clutch master support rod. Is it missing or just a funny angle?
     
  14. SquareRoot

    SquareRoot Full Access Member

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    I'd love to help you out but I'm getting ready to start my conversion on my K20 in the next few weeks. I bought a vacuum/manual assembly from a member on this site because I couldn't find a hydro/manual set. $300 and a week later I stumbled upon an 85 K30 in someone's driveway. I inquired about it and the guy let me take whatever I wanted for $350. Murphy's Law I guess.

    I took the assembly completely apart and rebuilt it my way. Rebushed it with a nylon bushing with a wall thickness of 1/8th inch and runs the full width of the new polished and hardened stainless steel "pin." Welded in a new 7/16 stud on the arm to attach the clutch pushrod to and threaded the arm to accept a rod end joint.

    All this extra work made this setup smooth as silk and I don't have to ever worry about wallowing out the pushrod holes/studs and replacing those cheesy paper-thin plastic bushing underneath the dash.

    Actually I lied. Three sets in my garage, one in my truck currently.
     
    Last edited: Oct 26, 2020
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  15. ajd89

    ajd89 Full Access Member

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    So I have a question I was doing some digging in the shed all these posts about swapping over to a manual. If you look close at the picture there is a extra hole on the brake pedal is that so you can use it for a hydroboost or vaccum brakes? The distance seems right. Mine has the hole as well
     

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