Need real-world exhaust advise

[84 Silverado]

Gents,
I just built a 350 with a little bit of a lumpy cam-dynoed at 351 horse, just a get around town motor and I'm not trying to set track times at Ennis.

It's time to think about exhaust and I'm going with shorty stainless headers and 3" inch exhaust. Given this set up, what muffler have you used that did not freakin DRONE? I've battled drone several times and I'd like to not have to swap out mufflers 2 or 3 times to get it right.

If you've been through this before and you know what I need, please let me know.

As always, thanks for your help.
Todd

 

[Turbo4whl]

Is your plan for a 3" muffler each header side, or one 3" muffler for both sides into a Y pipe?

 

[84 Silverado]

3" pipe from each header collector to muffler.

 

[Turbo4whl]

Not sure what will work for you, but I'll tell you what worked for me. First, we are talking muffler. The idea is to knock down the exhaust sound. Good flow through is secondary.

On the '74 350 long tube Hookers, I tried side pipes. Maybe look cool, but not very quiet. Put on a set of turbo mufflers. Different sound, still loud. Last, I put on a Walker stock style duel exhaust, now can play and hear the radio.

On the '82 with the turbocharged 5 liter, then the 402 Rat I went a different route. Used an International medium duty truck muffler, only one muffler. 3.5" in and out. Long 36" unit, about 9" round.

 

[goldpack]

My 86 350 is on factory original .... not loud at all. ..kind of a nice typical rumble to easily talk over....2 massive mufflers under the front of the bed,..no crossover between them,
just wish all that was outside the frame rail, and the gas tanks inside.

 

[Turbo4whl]

just wish all that was outside the frame rail, and the gas tanks inside.

Need a different truck for that feature, newer GM works.

 

[Ricko1966]

Gents,
I just built a 350 with a little bit of a lumpy cam-dynoed at 351 horse, just a get around town motor and I'm not trying to set track times at Ennis.

It's time to think about exhaust and I'm going with shorty stainless headers and 3" inch exhaust. Given this set up, what muffler have you used that did not freakin DRONE? I've battled drone several times and I'd like to not have to swap out mufflers 2 or 3 times to get it right.

If you've been through this before and you know what I need, please let me know.

As always, thanks for your help.
Todd

You know long tube's make more low end,and too large of exhaust diameter also doesn't give best low end. The stuff you picked would be better on a 600hp car for midrange and top end power. If you knew already sorry.

 

[76Bluec10]

I used Black Widow Venom series mufflers with long tube headers with 2.5”pipe not an overly aggressive sound unless you step on the loud pedal.
I’ve not really experienced any drone with this setup but then again not really driven much over 45mph.

 

[CalSgt]

I’m with @Ricko1966 on this one… 3” duals is just unneeded noise on a mostly stock SBC.

I’ll add that larger pipes are more likely to drone, google said so and everything on the interweb must be true!

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If you’re willing to re-think your pipe size I can confirm 2.25” duals with “super turbo” cheap mufflers sound great on a stock motor with a lumpy cam and should have minimal drone.

That being said quality resonators can make a world of difference on the drone front. I put the 2.5” version of this one on my Jeep because it was almost intolerable on the highway for any amount of time. The 2.5” version costs double of the 3” one for some reason but it did cure the majority of my drone issues. Resonators alone aren’t enough to eliminate annoying exhaust, instead use them to complement mufflers that produce a tone you like.

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Muffler and resonator location makes a difference too, the long straight portions of tubing are the most offensive for drone. Break those long straight sections up with your mufflers and resonators if you choose to run them.

I don’t have enough time behind the wheel on my most current SB build to say these mufflers don’t drone but I haven’t really noticed them to be annoying either. They are a little loud but not droning in the cab.

It seems to turn heads when I drive down the street, maybe because they have a totally different sound than the chamber mufflers that everyone seems to run on classics and V8 trucks.

2.25” Flowmaster HP2’s with Borla 4” tips that have resonators built in.

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[Radiohead]

I thought I would go 3" duals with long tube headers with the stock big block. Now I'm wondering if I might have went a little too big. Oh well, I suppose I could always add in resonator tips. I am still in the parts collection phase anyway...

 

[Finkaire]

I agree with the resonators, I have three chamber Flowmasters. When I got them they were too loud, getting old I guess. Shop recommended in addition to the Flowmasters adding resonators and guaranteed I would be happy. The resonators they put on are what I believe and look like Glasspacks. That is how they appeared to me, anyway the raspiness is gone and IMHO they sound great!!!
BTW, these are on my ‘68 Elco, can’t do too much with the P/U here in sunny California

 

[CalSgt]

I thought I would go 3" duals with long tube headers with the stock big block. Now I'm wondering if I might have went a little too big. Oh well, I suppose I could always add in resonator tips. I am still in the parts collection phase anyway...

3” duals may be slightly oversized for a stock BBC but still appropriate

 

[legopnuematic]

3” all the way is kind of pointless imo at 350hp, a single 2.5” or dual 2.25” would be just fine.

JMO, but I’d go with long tubes, unless if strictly required for fitment reasons, I have a hard time seeing the need for short or mid length headers. As I said, just my opinion.

I made these sidepipes for my 76, 2.5” tubing and resonators as mufflers, it’s not quiet per se, but is totally bearable noise wise ripping down the interstate and does not drone.

 

[Radiohead]

3” duals may be slightly oversized for a stock BBC but still appropriate

I wondered. I also figured that would be one less thing to have to upgrade when/if the engine gets a wake up. Hopefully a major wake up.

 

[DoubleDingo]

2 inch dual is plenty for a 350. It'll run just fine with 2 inch. Everyone always wants to go big.

I have a coworker with an 81 stepside, it had factory single, he went with 3 inch dual and it lost mileage and some power, but he likes the sound so he kept it.

I had never ran a vehicle with single exhaust until I bought my 81 C20, and I have to say I will always leave it as single. It's dual 2 inch for the y-pipe, that goes into single 2.5 inch, and out the back it drops to 2.25 inch. It runs greats, revs high, and has plenty of power, even with the engine upgrades. Nothing major, but it still runs great.