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Technical Glasspacks and back cackle

Discussion in 'The Hokey Ass Message Board' started by oldrelics, Mar 6, 2015.

  1. If you eliminate the tailpipe and just have the muffler as the end of the exhaust it might sound like what you want. My first car was a Yblock 292 and they are noted for that sound with glasspacks. I just had the muffler dump underneath the floor instead of having a tailpipe and it sounded totally different, more mellow and lower toned. Or perhaps larger pipes.
  2. Had a 68 Barracuda with a 340, sure made a difference with a shorter tail pipe, didn't have that ratty sound.
  3. They say that you want to get the muffler as far away from the source as possible, that is why most good exhaust shops put them just in front of the axle if possible. I guess that maybe it is the shorter tail pipes that cure the problem? learned something today. ;)
    1927graham likes this.
  4. Timbofor
    Joined: Dec 4, 2014
    Posts: 192


    On mine I pull a little timing out of it to calm down the cackle a little. It keeps my neighbors a little less angry. I'm running open pipes with no baffles though. When street vibrations is going on ( Reno sparks, motorcycle event ) I crank it up and let the pipes sing. The wife says it "makes the Harley boys cry". She's a keeper!
  5. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,250


    I'm just in the process of lengthening my side pipes by extending some 2 1/4" Cherry Bombs and using those in place of the short and small diameter inserts that are inside the existing extensions.
    Should end up with about 24" of muffler and room for a baffle hopefully.
    I once had a Mustang that I put "outsiders" on and the long glasspacks inside sounded awesome to me.
    HOPING this longer muffler setup for the T will be nice too but the Mustang was a 302 and this is a 454.
    Theres a lot more exhaust to muffle!
  6. Lobucrod
    Joined: Mar 22, 2006
    Posts: 4,122

    Alliance Vendor
    from Texas

    Flomasters dont to that.:p
    1927graham and 55Caddy62 like this.
  7. Put the glasspacks as close to the engine as you can, sweet music going downhill.
    SanDiegoHighwayman likes this.
  8. SmoKerch
    Joined: May 23, 2011
    Posts: 123


    I have back cackle if I eat too much chili.
    i.rant and SanDiegoHighwayman like this.
  9. Probably the best sounding exhaust I've ever had was flowmasters.
  10. metal man
    Joined: Dec 4, 2005
    Posts: 2,949

    metal man

    I have always called the sound you're talking about "hillbilly cackle", because I've seen a lot more clapped out pickup trucks driven by young guys with Wrangler jeans, shit kickers , and a waud of dirt in their cheek making that noise than hot rods.
    I can't stand that sound and have worked to figure out how to avoid it over the years. Here's what I've found, based on building probably a hundred exhaust systems over the last 20 years.

    Put the mufflers as near the back of the car as possible, short tailpipe.
    Use a larger diameter tailpipe ( 2 1/4"- 2 1/2")
    Use an H pipe somewhere near the front universal joint if possible.
    That pretty much does it, no matter what mufflers you use, but I almost always use an all stainless muffler. I usually use Stainless Specialties "turbo tone" mufflers on early cars.
    I hope that helps.
    Last edited: Mar 7, 2015
  11. back in the day we would get em real hot, 15 -20 minute drive and then shove a water hose in there and hit em with cold water, then crank em up and watch the poop blow out.
    doesnt help a damn bit with your question, just thought I would let ya know the memory you jogged.
  12. metal man
    Joined: Dec 4, 2005
    Posts: 2,949

    metal man

    The best sounding system I've built recently .... 428 SCJ, 10.5:1 compression , 2 1/2" mandrel bent exhaust out the back, with flowmasters as far back as I could fit them. It also had an H pipe.
  13. Tony
    Joined: Dec 3, 2002
    Posts: 7,350


    Had stainless packs with 2.5" pipes on my 57 at one point.. Loved the low rumble at idle and steady cruise speeds, but the crackle/popping at high rpm's and down shifting sucked...big time.
    I fixed it by taking them off...
    After building a pretty healthy mill for it i was tired of it sounding like a misfiring farm tractor.
    No offense meant to anyone who likes the sound of em....we all have our own likes and dislikes.

    The suggestions given sure sound like some very good ideas to try and cut back on the rapping...

  14. George G
    Joined: Jun 28, 2005
    Posts: 1,274

    George G

    Back cackle? We used to call That reverse rap.
  15. Put stock mufflers on it, then
    Just get this guy to ride with you.
    Tell him what you want it to sound like.

    Last edited: Mar 8, 2015
    i.rant likes this.
  16. chevy57dude
    Joined: Dec 10, 2007
    Posts: 6,397


    31 - That's a hoot!
    Just ran thru the thread again, and it's worthy to note the direction of flow in glasspacks. Look in the end of the muffler. In one direction, the gasses would try to enter the perforations toward the glass packing. Reverse the flow, and the gasses "ramp over'' the holes. More noise that way but the packing doesn't blow out so fast. Just the way I like it!
    The short tailpipe post is interesting. Good info there.
  17. B.A.KING
    Joined: Apr 6, 2005
    Posts: 3,760


    when I "BACK CACKLE" my wife makes me leave the room.! just sayin.........
    SanDiegoHighwayman likes this.
  18. My thoughts exactly!!
  19. Well I would say TMI but that's sounds like a bean statement. ;)
  20. SanDiegoHighwayman
    Joined: Jun 26, 2012
    Posts: 951


    LOVE the sound of a 312-292 w large dia dual exhaust [ no H pipe ] ALL my Fords & Mercs have HAD it :)

    here's what it sounds like

    LOVE it! :D
    Last edited: Mar 9, 2015
  21. COOP
    Joined: Mar 27, 2006
    Posts: 258


    Ain't nuthin' sounds as good as a Y block with glasspacks.......... unless it's a split 6.
    SanDiegoHighwayman likes this.
  22. Tony
    Joined: Dec 3, 2002
    Posts: 7,350


    Now, i gotta admit i had a 53 chevy running a 235 and a split manifold with real short stainless packs wayyy up front, full 2" pipes and 3" cans out under the bumper....
    The exhaust rap from THAT i loved!! :)
  23. manyolcars
    Joined: Mar 30, 2001
    Posts: 8,484


    I have heard this all my life too. If you do this, stand well clear of the hot water and STEAM coming out of the pipes. Severe burns, from hip to ankle, many many emergency room visits, a month of watching the doctors pulling your flesh off so that you will able to walk again and weeks of physical therapy after that. Scars too
  24. DDDenny
    Joined: Feb 6, 2015
    Posts: 15,059

    from oregon

    Had a set of the first PURPLE HORNY (remember them, the big ones) direct to header mufflers early 70's on my 57 Bel Air, I could probably hear what my wife says if it weren't for them. She's always saying that I don't listen to her.
    I call it selective hearing.
  25. flux capacitor
    Joined: Sep 18, 2014
    Posts: 676

    flux capacitor

    Hands down loudest muffler I ever had , walker "turbo tubes" got them in early 90's rippled shell glass packs , the box read "GRRRRR!!!!!! Just like the 60's." Put them on a weenie 305 w headers & oh my gosh! Crackled on acceleration & decibels were off the chart! Louder than my 302s chambered pipes. Short lived availability but man I wish I still had them. Had gear heads asking what I'd done to that engine. If love to hear them on a mean buzzin 1/2 dozen, that'd be down right spooky sounding. I found a pic of some! Flux image.jpg
    Last edited: Mar 9, 2015
    bowie likes this.
  26. 53CHKustom
    Joined: Jun 24, 2014
    Posts: 1,433


    Wow. I have been spinning my wheels trying to figure out how to get that sound when you let off the pedal. Wish we could trade setups!
    wraymen and flux capacitor like this.
  27. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,250


    The T has been running those generic glasspack inserts in the side pipes...about 12" long with a 1 1/2" louvered core doing its best to choke up the 454.
    Just finished building some new mufflers by cutting apart four 2" core Cherrybombs and combining the pieces into some 30+" glasspacks. HOPING these will, in addition to freeing up the exhaust flow a little, give a lower deeper rumble.
    I'll be adding a cowl piece to the back end and running some 2.5" chrome turnouts much like the pipes on Cotton Werksman's Ardun powered Modified.
    Any thoughts on how it will sound...or the look for that matter? :D

  28. Shaggy
    Joined: Mar 6, 2003
    Posts: 5,208

    from Sultan, WA

  29. SanDiegoHighwayman
    Joined: Jun 26, 2012
    Posts: 951


  30. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,274


    Back rapp is the best part if you don't like it shift to neutral it will only last a short time.

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