Exhaust/Mufflers

[Acregger]

Hey guys getting about time for exhaust for my 71 k10 with a 5.3, just trying to see what you guys went with. I have had very good luck and like the sound of Magnaflows in the past but torn between 14 inch and 18 inch. I dont want it terribly loud but sound good. It little hard to listen to the sound on you tube as all the Silverado's on there have cats. Seeing your thoughts and maybe a sound clip.

Thanks

[kipps]

I'm in a similar position. At this point, I'm looking at using a single Magnaflow Delta 50 or Delta 70 muffler. I don't mind a little rumble, but I don't want it to be loud at all. I will be installing cats on mine. I don't know yet whether I'll install a resonator or not.

[1971Stepside]

I bought the Hooker Blackheart set up. Fit great, but it does need the holes cut in the trailering arm cross member.

[Acregger]

Originally Posted by 1971Stepside

I bought the Hooker Blackheart set up. Fit great, but it does need the holes cut in the trailering arm cross member.

What kind of modifications to hook to a 4x4 truck and the LS?

[1971Stepside]

What kind of modifications to hook to the truck and the LS?

None, if you have the holes already cut in that crossmember. The kit is designed to sit inside the frame rails and not hang down under the frame. You will also have to work out making the connection to your headers/manifolds to the pipe since they all differ, but that is pretty simple to do. You can look at the Blackheart thread in this LSx Swaps section or look at my build thread (1971 Stepside LS Build) to see more pics.

[Acregger]

Originally Posted by 1971Stepside

None, if you have the holes already cut in that crossmember. The kit is designed to sit inside the frame rails and not hang down under the frame. You will also have to work out making the connection to your headers/manifolds to the pipe since they all differ, but that is pretty simple to do. You can look at the Blackheart thread in this LSx Swaps section or look at my build thread (1971 Stepside LS Build) to see more pics.

Cool, I looked at the website under my truck and LS swap but didnt show a kit

[1971Stepside]

https://67-72chevytrucks.com/vboard/...d.php?t=790866

[Captainfab]

The 2wd Hooker Blackheart LS exhaust is not going to work on a 4 x 4 without modification

[1971Stepside]

The 2wd Hooker Blackheart LS exhaust is not going to work on a 4 x 4 without modification

Great point! I missed the "K" in 10. Thanks Captainfab

[Joemomma1]

I have flowmaster 40 series on my 5.7 and its too loud. Wasn't a big deal as a kid but it is as an adult.

[bigmoe]

I went with Magnaflow XL 3 chamber mufflers. I wanted something not too loud. At first I just had turn downs behind the mufflers and there was a lot of drone. Tailpipes to the back helped that. Not quiet by any means but tasteful and of course louder when you tromp on it. If anything it has too much "slap" when I step on it. May try some resonators. I have shorty headers.

[kipps]

Originally Posted by bigmoe

I went with Magnaflow XL 3 chamber mufflers. I wanted something not too loud. At first I just had turn downs behind the mufflers and there was a lot of drone. Tailpipes to the back helped that. Not quiet by any means but tasteful and of course louder when you tromp on it. I have shorty headers.

Can you explain what you mean by drone? I've been hearing the term for some time, but haven't been sure. Is it simply exhaust note in the cab, or is it something worse?

Reason I ask, I'm building the truck in my signature, and I WANT to clearly hear the engine in the cab, but I want it as quiet as possible outside the truck. It's fun to have a deep exhaust note when rowing the gears, but I don't want the neighbors to say, "There he goes again..."

I know this truck will have less insulation on the firewall than the donor Tahoe did. I don't know how much I'll hear the engine itself through the firewall, without needing to add the exhaust note to it as well.

I've driven two trucks extensively that had a single glasspack and a turn down exhaust underneath the bed. One was a 1973 f100 with a 360fe, and the other is a 1981 f150 with a 300i6. I'm currently driving the second one. I've really enjoyed the exhaust note of both, and feel it's about perfect, aside from the crackling on deceleration. I've been really surprised how quiet each truck has been, which doesn't make sense with the glasspacks.

[bigmoe]

Drone is at lower rpm. It's a loud and echoey hummmm. Lol I'm trying to figure out the best way to explain. Maybe try youtube exhaust drone.

[Acregger]

I am in the same spot, dont want the drone. I like to hear it and it have a good sound but not terribly loud. I think I may just have a guy do custom exhaust and hope for the best.

[nsb29]

What’s quieter flomaster 50s magnaflow 70s ?

[Custom 68]

Borla mufflers can be expensive but I have used them and recently installed one on my newer truck. They have a nice rumble on startup and idle but seem to calm down when driving. They will roar when you get on them.
I had this on my 68 but with the turbo and resonator it was quiet. I am trying something different on it, the turbo changes it significantly.
Dave

[nsb29]

Had exhaust put on my truck yesterday went with the flow master 50s not impressed much louder than I expected from what I had heard but what I dislike the most is when you rev it up it has a crackle when you let off Sounds like sh t

[Acregger]

Originally Posted by nsb29

Had exhaust put on my truck yesterday went with the flow master 50s not impressed much louder than I expected from what I had heard but what I dislike the most is when you rev it up it has a crackle when you let off Sounds like sh t

That worries me too, I dont like that crackle either.

[Steve Cole]

Originally Posted by nsb29

Had exhaust put on my truck yesterday went with the flow master 50s not impressed much louder than I expected from what I had heard but what I dislike the most is when you rev it up it has a crackle when you let off Sounds like sh t

Funny you mention the crackle. I just had my exhaust done due to the LS swap and now I have the crackle. I never had it before when i had the SB 350 and I am using the same Magnaflow mufflers I used then. Three differences between the old and new exhausts- the old system had an "X" pipe installed where as now it is just true duals and also the mufflers are further towards the rear of the truck than before and lastly I am running mid-length headers now and had long tube headers before. My system is actually quieter than before but when you get in the gas it sounds like crap. Is your exhaust a true dual setup?

[nsb29]

I have the cast manifold that came with the motor which is from a Pontiac G8 I believe similar to the Camaro cast manifolds from there is 2 1/2 inch exhaust back to the mufflers and then exit behind the rear wheels I did not use an H Or X pipe driving down the highway it really isn’t that loud but going through the gears it’s louder than I wanted I am considering installing two small glass packs behind the mufflers in a straight area about a foot and a half from the end I also wondered if it was because I did not install an H or X pipe ????? I also wondered if it was the brand I bought and maybe I should have bought magnaflows but if you’re having the same problem that’s obviously not it if you figure out something before I do post it I’ll do the same

[aknovaman]

cackle is partially caused by decel timing and fuel settings in pcm file. a tuner can adjust that out.

[nsb29]

Thanks for that information my plan has been once the truck is 100% done taking it to a tuner I think I may still add the glass packs just to help mellow it out some

[bigmoe]

Some people add resonators in the section before the mufflers. You can get some after market resonators that are about 12" long and fairly small in diameter. Great for reducing drone too. Summit has Vibrant brand which are reasonably priced.
Edit: From what I've been looking at for resonators most are basically glass packs in various lengths. I think I might try some glass packs before the muffler to reduce the "slap" wet fart sound when tromped or revved up.

[nsb29]

Never used them I thought they went after I’ll look into it

[aknovaman]

GM 3800 v6 cars have resonators between the cats and the muffler. Removing them creates a terrible rasp and fart noise at idle. They are essentially a perforated glass pack design thats straight through.