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DoubleDingo's '81

Discussion in '2wd Pick-Ups C/R 20 2500 C/R 30 3500' started by DoubleDingo, Jul 30, 2012.

  1. Honky Kong jr

    Honky Kong jr Super Sarcastic Man

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    Lil BB 407
    You think that’s bad try Manhattan or Boston.....lol
     
  2. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    First Name:
    Bagoomba
    Truck Year:
    1981, 1965
    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    It's a little thing, but it looks better with the covers over the strap. Thanks @bucket

    Well I tried to upload the photo last night, but it appears I missed a step. So let's try this again....


    Chrome Covers.jpg
     
    Last edited: Apr 11, 2019
    Rusty Nail and bucket like this.
  3. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    First Name:
    Bagoomba
    Truck Year:
    1981, 1965
    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    When I got this truck it never did run great. Just figured it was the nature of the beast because of all the extra gadgets under the hood, and everything being old. I rarely drove the truck because it run so crappy. Was embarrassed to be seen in it sometimes. But it had its moments of greatness where it ran well and put a smile on my face and making me proud to own it.

    So yesterday I investigated the vacuum hose routing and conditions of the lines. I didn't have enough 3/8" to replace those. Did replace a small purge hose that was contributing to the big vacuum leak. Someone put on bigger hose and a tiny zip tie to clamp it down. Smaller hose installed so it seals, and that leak was fixed.

    The leak at the air cleaner was user error. The rubber piece with the three ports, yeah, stupid me had one port on, one port off. With the vacuum leaks fixed this thing just purrs. I mean it's music to the ears, and it no longer has a strong exhaust smell. Amazing how something so small can make such a huge difference

    I'm now on the "check for and fix all vacuum leaks first" boat. If I had done this years ago this truck would have many more miles on the odometer.
     
  4. Craig 85

    Craig 85 Full Access Member

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    First Name:
    Craig
    Truck Year:
    1985
    Truck Model:
    K30 SRW
    Engine Size:
    454/TH-400/NP205
    Since my truck had been off the road for 10+ years before I bought it, I went through and replaced every vacuum line and all the emissions sensors. It runs great. Another vacuum leak I found while replacing the lines was the diaphragm for the air cleaner snorkel. I was able to modify one for a Firebird and make it work.

    I recently hooked up the HVAC system and found there is some type of leak in the inside the cab in one of the pods. It runs fine when warm, but has a hard time starting when cold.
     
  5. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    First Name:
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    Truck Year:
    1981, 1965
    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    Pretty sure the exhaust system on this truck is the original pipes, muffler, not sure. Either way I got tired of the sound it produced. It sounded okay, but at certain rpms it wasn't cutting it. So I got the longest Thrush glasspack for 2.5 inch exhaust(25 inch body, 28 inch overall), and not wanting it to be really loud, I got the shortest Cherry Bomb glasspack(8 inch body, 12 inch overall) as a resonator. Had them welded in this morning. The short one upstream, and the longer one where the old muffler was. He angled it so he didn't have to redo any of the pipe. On the drive to work I liked the sound. Way better than it was. On my morning break I took a quick drive to pay the cell phone bill. I think I picked up 10-20 ponies! The truck pulls harder than it did with that old muffler on it and broke the tires loose when I got on it. And all I had him do was remove the old muffler and install the two glasspacks. It's quieter than it was, but has a nice rumble now. Definitely an upgrade.

    Got these pics during lunch...

    Resonator...
    Resonator.jpg



    Muffler Replacement looking from passenger side....
    GP from PS.jpg



    Muffler Replacement looking from driver's side....
    GP from DS.jpg
     
    Last edited: Apr 22, 2019
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  6. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    First Name:
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    Truck Year:
    1981, 1965
    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    Sure liking the improved power band on this thing.
     
  7. bucket

    bucket Super Moderator Staff Member

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    Truck Year:
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    Truck Model:
    K5 thru K30
    Engine Size:
    350-454
    Yeah, I think the factory mufflers were fairly restrictive. And the average replacement was extremely restrictive. They often necked down to around 1.5 inches on the inlets and outlets.
     
  8. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    Truck Year:
    1981, 1965
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    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    I noticed, too, that it's 2.5 inch pipe up to the muffler inlet, then the tailpipe over the axle appears to be 2 inch.
     
  9. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    Truck Year:
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    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    My wife is off today, and during lunch I had her stand outside to hear it as took off to go back to work. She actually had something good to say about the truck. She may become a believer after all...lol...
     
  10. Craig 85

    Craig 85 Full Access Member

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    Truck Model:
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    Engine Size:
    454/TH-400/NP205
    That's correct. When I bought my truck it still had the factory GM mufflers and oval tips with the mesh screen. I didn't realize the HD trucks came with single exhaust. My 1980 and both my 85's had duals, but all of them were 454 trucks.

    IMG_1144.JPG
     
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  11. HotRodPC

    HotRodPC Administrator Staff Member

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    454 - Turbo 400 - 3.73 350 - 700R4 - 4.10
    Man don't say that. I like my factory OEM 454 dual exhaust. It's quiet and all you hear when you get on it is Carb roar.

    84bedchange 012.jpg
     
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  12. bucket

    bucket Super Moderator Staff Member

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    Was that a California thing? My old '86 454 Burb had the factory duals and it didn't have any special tips.

    That's what mine looked like. Round mufflers and the downpipes had heat shields fully around them. I never got around to changing the exhaust to get a side by side comparison.
     
  13. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    Truck Year:
    1981, 1965
    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    I have a link in my bookmarks for Walker Exhaust so I looked it up out of curiosity. 2.5 to the muffler, 2.25 out the back.
    Mine is a 350, but when I need to get a trans filter and gasket I have to say it's a 454 if I go to Pep Boys because for some reason a 350 didn't have a TH400 behind it according to their books.
     
  14. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    First Name:
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    Truck Year:
    1981, 1965
    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    I was wanting to get a muffler like those there, but they didn't have them, so I went the glasspack route.
     
  15. DoubleDingo

    DoubleDingo When In Doubt, Throttle Out

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    First Name:
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    Truck Year:
    1981, 1965
    Truck Model:
    81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
    Engine Size:
    Carb'ed Vortec 350; 1972 L48 350
    Not sure on the CA thing. The guy was going to cut off the screen on the tip of the exhaust, but I did that years ago.
     

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