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Projects Exhaust suggestions for mild (330ish HP) SBC 350

Discussion in 'The Hokey Ass Message Board' started by Master Brian, Apr 11, 2018.

  1. Master Brian
    Joined: Apr 10, 2017
    Posts: 144

    Master Brian

    I'm ready to order a few parts and get the exhaust installed on my '60 suburban with the above engine. It's got an Eddy 4 Barrel, an ISKY 270/280 Cam and some other mods done. Machinist said it's probably a 330ish HP engine.

    In any case, currently I'm running one 2" Ram Horn Manifold and one 2" truck manifold through a 2" exhaust pipe. The mufflers are I think just basic 5" round about 15" long mufflers and then tailpipe out the rear corners after the wheels. The mufflers are rusted out, so it has some obvious sound to it, which everyone seems to like, including myself. That said, it is time to even things up on the Manifold/Header front and take care of the leaky mufflers.

    I've been trying to listen to YouTube sound bits of different mufflers and setups, but obviously it gets confusing and tough as it's actually kind of tough to get the same camera angle/sound and the same engine type/setup. That said I had sort of decided I liked the Borla XR1 Sportsman, but they are a bit pricy(though doable), but the shops seem to try to steer away from them as they are a 3" outlet & inlet and thus makes tucking them up under my truck more tricky as it's lowered 5" in rear with coils in the trailing arm suspension. Up front I have 2-1/2" drop spindles then torsions cranked down another 2-3" to give it the hot rod rake look.

    One shop suggests more of the Flowmaster 40 series as I had a set on a 1999 K1500 Suburban with 5.7l vortec and I liked the sound of it. The other shop recommends the Magnaflow Mufflers and said he's had great luck fitting their 5x8x14 mufflers under this X Frame. He doesn't think the round Borla will fit, but as I said my current leaky mufflers are 5" round.

    They both say 2-1/2" is going to be tricky and thus suggest 2-1/4" pipe at the biggest. The one said nothing wrong with my current 2" pipe, just new mufflers and tail pipes, BUT as I said the mani's aren't matched.

    Through talk online with this era truck forums headers seem to be very tricky with this suspension and frame, almost everyone suggested the 2-1/2" ram horn mani's, but Summit says Sanderson makes a Shorty that should fit great and has excellent reviews. Cost is about $150-175 for the Ceramic coated Ram Horns, about $325-350 for the bare steel Sandersons and over $500 for the ceramic coated.

    Cost is always a consideration, but I will do whatever is best as I don't want a regret and at end of day a few hundred more isn't the end of the world for me. That said, I don't want to throw my money away either. The truck is purely street use, I won't take to strip and am not a street racer either. I just want a nice sounding (I do like some throaty old school hot rod sound). I also want to hear the cam lope, etc... Truth is what I've heard on all 3 mufflers they all sound really good.

    I guess my question is, am I holding the engine back noticeably with the Ram Horns over Shorty's, what about 2-1/4" vs 2-1/2" pipe? I'm guessing any of those mufflers will perform well. Do I just stick with the mani's I have, keep the 2" pipe, keep 3bills plus in my wallet and just swap out the mufflers? I'm also thinking I want an H pipe and tests do seem to show they help low end. The one shop said they quiet things down though....I heard they add more of a low rumble....is that just the engine sounds coming though more?

    In any case, anything is helpful. If the magnaflow's are just as good as the FlowMaster and Borla, they seem less expensive and reviews seem excellent. With the Magnoflow's I was quoted about $600 for the complete exhaust Manifold back. Obviously they H pipe will add about $100. If I go with the Headers and the Borla's I'm over double the cost and wondering if that's anything I'd ever notice.
     
  2. You are way overthinking it. Get a pair of truck manifolds or if you want to spend money get yourself some full length headers for it (1 5/8" primaries) and rune 2 1/2 exhaust all the way back. A pair of 28" long glass packs with muffle it just fine.
     
    31hotrodguy, wraymen and pitman like this.
  3. XXL__
    Joined: Dec 28, 2009
    Posts: 2,001

    XXL__
    Member

    What @porknbeaner said, 'cept the long tube headers are going to drag the ground because of your drop.

    Also, there is a fair amount of room to run typical oval mufflers (like the welded Flowmaster types or the "turbo" mufflers) just in front of the rear axle. I've got some on one of my old trucks, and they're turned sideways so the long side is up and down. Mine is a truck, so I don't have rear seat floor,pans as low as you do in the Suburban, but there is plenty of room to run them flat just in front of the axle.
     
    Truckdoctor Andy likes this.
  4. Sheep Dip
    Joined: Dec 29, 2010
    Posts: 1,572

    Sheep Dip
    Member
    from Central Ca

    Flowmaster Super 40's with an H pipe
     
    Tickety Boo likes this.

  5. buck 32
    Joined: Oct 16, 2014
    Posts: 182

    buck 32
    Member
    from Maryland

  6. I've got two cars with Flowmasters and I'm so over them. Can't really afford to change out perfectly good mufflers right now, but wish I could.
     
  7. buck 32
    Joined: Oct 16, 2014
    Posts: 182

    buck 32
    Member
    from Maryland

    I agree
     
    lothiandon1940 likes this.
  8. I have a 76 3/4 ton with a 454, 280 comp cam, and am running full length 1 3/4 Hooker headers with 2 1/2 pipes from the collector back. I am using Dynomax turbo mufflers, and it has a nice deep sound.
    I don't know if there is much difference between your 1960 and my truck, but the header pipes are 2 1/2 inches of exposure below the frame. I don't think the full headers would work well for a lowered truck.
    Considering that you are not racing, why not use a good set of shorty headers. This way, the exhaust pipes from the collectors back will not be exposed.
    From my experience, the larger the diameter of the tail pipe, the deeper the sound.
    Bob
     
    Master Brian likes this.
  9. Can't believe your exhaust/muffler shops not going with 2 1/2 in pipes..............have used this size on all my cars without any problems or issues..........on mufflers, I have MagnaFlows, FlowMasters plus some "no name" cheapies and all sound just fine, 'cept the FlowMasters are getting loud so likely will be changed soon............on exhaust manifolds, have several sets of "shorty" headers w/VHT paint and 1 pair is Ceramic coated, also using 2 1/2 in ram horns on my 383 stroker 65 Impala wagon.........this ride has factory a/c and the stock ram horns had all the factory mounts, etc req'd.............lastly, have H-pipes on several and don't notice any sound differences.........
     
  10. DDDenny
    Joined: Feb 6, 2015
    Posts: 15,155

    DDDenny
    Member
    from oregon

    I built a similar 350 for my 66 Suburban many years ago, 15/8" shorty headers and Walker turbo mufflers, one thing I noticed on mine was a horrendous "drone" at freeway speeds, boy did that get old.
    You may think Flowmasters are cool sounding but I predict you'll hate them on your Suburban too.
    I think the cavernous interior of the older Suburbans needs some serious insulation to overcome this regardless of the choice of muffler.
    Don't get me wrong I love them, spent many thousands of miles in my friends various hot rods equipped with Flowmasters.




     
    XXL__ likes this.
  11. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,774

    Blues4U
    Member
    from So Cal

    In these muffler threads, there are usually as many opinions as there are people who post, good luck sorting that out.

    FWIW, this is a traditional car forum, and Flowmaster's are not traditional in any way. If you want your Sub to have a classic exhaust tone, you won't get it with Flowmasters or H pipes.

    I think Beaner gave you the best advice, with truck manifolds -> 2 1/2" pipes, glasspacks will be nice and loud, 2 1/2" turbo mufflers will give it a more mellow tone. Pipe size should be 2 1/2" out to the rear bumper. Muffler shop probably doesn't have dies for 2 1/2", that's why they're trying to talk you out of it.
     
    bchrismer and Truckdoctor Andy like this.
  12. Master Brian
    Joined: Apr 10, 2017
    Posts: 144

    Master Brian

    That's why I ask, will I notice a difference with 2-1/2" vs 2-1/4"?

    As for headers, I'm told from people with this year and frame the full lengths will not work without possibly a lot of tweaking. I don't want a lot of issues, so either shorties or Ram Horns....leaning towards the Ram Horns simply because I think they'll be less maintenance, they are cheaper and am not convinced they'd be that much of a sound/performance upgrade on the engine I have. What is your take on the Ram Horns on your 383 vs your other cars with shorties?

    Is the H-Pipe worth the $100?
     
  13. Master Brian
    Joined: Apr 10, 2017
    Posts: 144

    Master Brian

    I'm not trying to over complicate, just need to make certain I get the right mix/match to make it simple and not lots of extra work. (pertaining to earlier post(s).

    Not sure how much hwy driving I'll be doing as it's a T350 Tranny, but I don't want it to be annoying either, which is why I'm asking. On my 99 K1500 with true dual exhaust the Flowmasters aren't in the least annoying, except to maybe my neighbors as people tend to say it's loud.....err at least they know I'm coming. That said it is a far different beast than the '60.

    I think glass packs would get old quickly as well. I had them on an old 78 Jeep CJ5 with 304 AMC and they were fun when 20, not sure I want that much noise now.

    How much will those drone in the 60 Burb I wonder. I see they sell resonators as well, wonder if all of that can tuck up under. They do sound good, but again...wonder if too much like the old glass packs. Hmm....
     
  14. XXL__
    Joined: Dec 28, 2009
    Posts: 2,001

    XXL__
    Member

    The cross section of 2.5" tubing is ~5 sq. in. Cross section of 2.25" is ~4 sq. in. That's 25% more "flow" out of the bigger (exhaust scavenging and fluid dynamics are more complicated topics than that... just go with it for the sake of this thread). More flow is _generally_ better (again, it gets complicated... but not so much in your setup).

    Ram horms will last foreverrrr. Budget headers, 2-10 years, depending on heat cycle and condensation. Good, coated headers... longer, but not foreverrrr.

    H-pipe has some technical value in exhaust scavenging and pressure equalization... but you won't notice it in your setup. The $100 part is your call.

    /2 cents
     
  15. Master Brian
    Joined: Apr 10, 2017
    Posts: 144

    Master Brian

    XXL, thanks. I think I'm going to order the Ram Horns. Just seems to make sense on this setup. I also know the 2-1/2 in theory is better and then 3" is better yet, but I do know 3" will cause issues on my setup. I'll try to push the 2-1/2", not sure why they can't do that and if not, I'll go elsewhere. As for clearance, the pipes do hang down low and are one of the lowest parts of my setup, BUT currently the torsion keys are lower at the point where it matters. At some point, I'll have them re-clocked so they don't hang down. I thought the shop was going to do that when they aligned it and turned them down, but alas they didn't and I do occasionally rub them so I have to be careful.

    Now to determine the mufflers. I think it's either the Magnaflows or the Classic Chambered....i like the idea of more traditional of the Classic, just worry they'll really drone. I get some now and most of my driving is around town at the 1800-2200 rpm range.
     
  16. DDDenny
    Joined: Feb 6, 2015
    Posts: 15,155

    DDDenny
    Member
    from oregon

    Not understanding your logic, 350 turbo trans and hiway use?
    BTW, I'm using the same transmission in my Suburban.

     
    XXL__ likes this.
  17. flatheadpete
    Joined: Oct 29, 2003
    Posts: 10,204

    flatheadpete
    Member
    from Burton, MI

    I run Powerstick mufflers on my '50 Ford with a stout 302. 2 1/4" from shortie headers all the way to the bumper. Doesn't drone bad, has a nice rumble at idle and low speed yet has a little bark on accel. On top of all that, they really aren't too expensive and they're made in Michigan (a HUGE thing to me!).
     
  18. XXL__
    Joined: Dec 28, 2009
    Posts: 2,001

    XXL__
    Member

    This is all about resonant frequency. When something generates a frequency, things around it want to vibrate sympathetically... because those sound waves from the source are hitting the other parts. Big, thin pieces of sheetmetal (like a Suburban rear) are very sympathetic. 1/4" plate, less so. 10" concrete slabs, even less. But, you probably don't want to replace your sheetmetal with 1/4" plate or concrete. So..l there are 2 other options... 1) 'sound deadeners' are typically designed to convert energy into lower frequencies (it is not simply 'insulation' as many think). As the resonant energy enters into the deadener, it must do a lot more work to get the deadener to vibrate... because the deadener has a much lower resonant frequency. That conversion effectively dissipates a lot of the energy... so... more quiet; and 2) get the noise-maker to resonate at a different frequency... this one is more difficult because you can't reasonably just try out different mufflers like you do shoes at the shoe store. What I can offer here is that, #1 above is your first line of attack, and for #2, if you can get a muffler with as stiff a case as possible (ie, heavy gauge welded case), it will, assuming comparable internal baffling design, have less resonance than a thin sheetmetal case with rolled end caps.

    There is a LOT more depth to acoustics, but my fingers are tired and we could easily get into the weeds on an otherwise simple problem.
     
    Hnstray likes this.
  19. pitman
    Joined: May 14, 2006
    Posts: 5,084

    pitman

    Ran 2" pipes behind a 375 hp 355ci SBC for 20k miles. 2-1/4 would work, and clear easily. (a deep bass note is result of expanding the last foot or so of pipe, hence, fart cans on Ricers.)
     
    Last edited: Apr 17, 2018
    Jrabbitknox likes this.
  20. badvolvo
    Joined: Jul 25, 2011
    Posts: 472

    badvolvo
    Member

    < 2.5" with x pipe, flowmaster's = great sound and performance.
    A lot of muffler shops can't bend 2.5", so they recommend 2.25.
     
  21. Run the 2" out of the manifolds to about the end of the transmission and bump it up to 2-1/4 to the muffler and 2-1/2 inlet 2-1/2 tail pipes then the longest section of 3" at the end.
    Keeps your velocity up ( torque) lets it flow as things cool off and slow down and the 3" end will deepen the note. Symmetrical pipes look nice but the symmetry increases drone.
     
    pitman likes this.
  22. indyjps
    Joined: Feb 21, 2007
    Posts: 4,282

    indyjps
    Member

    Check out walker turbo mufflers. Walker is the parent company for dynomax. They offer a wide range of size inlet outlet. I put them on everything. Want it quiet, get long walker turbos, loud-short.

    I like 2 1/2 pipes, tell your muffler shop to stop being lazy. :) 2 1/2 pipe will generate some drone, put your mufflers farther back in the system, or start out smaller diameter and step up at the muffler.

    2" ramhorns should be fine. 1 5/8 longtube would be my preference for a heavy vehicle with that range cam. Understand your ground clearance issues.
     
    pitman, Chavezk21 and lothiandon1940 like this.
  23. southcross2631
    Joined: Jan 20, 2013
    Posts: 4,414

    southcross2631
    Member

    Auger mufflers from Speedway . Light , cheap and fit inside the pipes so no matter how low you won't drag a muffler. They sound awesome .
     
    Blues4U likes this.
  24. XXL__
    Joined: Dec 28, 2009
    Posts: 2,001

    XXL__
    Member

    The OP doesn't have a 'too low' problem. He has an installer problem. My C10 is a hair over 48" tall, and my exhaust has zero ground clearance issues.
     
  25. Master Brian
    Joined: Apr 10, 2017
    Posts: 144

    Master Brian

    Not that it can't run on the HWY with that transmission, just that I doubt I spend much time running it on HWY because I hear the T350 will wear on you after extended HWY use. Hence the reason lots convert to the 4speed trans.

    At this point, I also don't have lots of reasons I'd have a need or desire to get her up on the HWY. She's still fairly rough body wise.
     
  26. XXL__
    Joined: Dec 28, 2009
    Posts: 2,001

    XXL__
    Member

    No difference between the two at highway speed. You aren't clutching or shifting and top gear ratio for both is 1:1

    (Somebody pointing out the NP440 in 3...2...)
     
  27. Millions upon millions upon a lot of turbo 350s & 400s and even power glides collectively logged trillions of highway miles.

    The reason the auto makers needed a 4speed OD trans was to over come engine anemia with lower gears and then OD to get milage back
     
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  28. Master Brian
    Joined: Apr 10, 2017
    Posts: 144

    Master Brian

    Thanks! The 60 Burb actually doesn't have a sheetmetal bed like the newer ones it's 3/4" plywood. It was overlayed with cutback paper(or whatever they used back then) and then had something like a vinyl covering. I got the cracked and pealing vinyl and other layers off, I'm now down to the black tary substance. I thought about a nice vinyl, but am leaning towards getting some vintage oak flooring and planing it down from 3/4" to under 1/2" thick to save weight and thickness. Or I might just create my own flooring from some other old lumber and try to find a good way to adhere it to the ply. Not sure if I can add a deadener in between without raising the floor too much and making things look funny or if it'll have to be done from the underside. I did start spraying the underside with truck bed coating and/or undercoating to protect it and clean things up. At this point, it won't be a ground up resto any time soon, so trying to keep it from getting worse.

    As for #2 those classic chamber mufflers look pretty solid, so I might give that a go and if too much drone, I'll see what I can do....they do sell a resonator, so if I have them leave enough room in the system, they could come back and add them at a later time. I'm really thinking I like those over any others and it does seem to sound more old school.
     
  29. Master Brian
    Joined: Apr 10, 2017
    Posts: 144

    Master Brian

    Then I was misinformed. I thought the 4 speeds (forget the popular convert from T350) had a gear that kicked the RPM's down, thus making it more HWY friendly. I realize lots of miles put on those transmissions as well, but the speed limits are also much higher now, at least in the last 4 decades that I've been around. Mileage would be another reason at this point as I'm suffering in that dept with my 3.90 rear diff. Never the less, I still don't really feel much desire to make long drives with my burb at this stage and thus the reason I'll keep her off the hwy for now. The front suspension is all new, so that's solid, but rear diff is still in debate as it's the original 3.90 posi and it's missing a few clutch guides. I'll replace it at some point, but for now....back to the exhaust!! ;)
     
  30. XXL__
    Joined: Dec 28, 2009
    Posts: 2,001

    XXL__
    Member

    2018-04-12 21.17.26.jpg
     

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