Exhaust size
 

What are you guys running for dual exhaust systems? Lookin to see what most guys are running, mine has 2 1/4 seems extremely popular wiht these style trucks, problem is my 4 banger s10 system is louder than my k20 true dual system same exact flowmaster 40 series muffler?? Anyone running a 3 inch system, or will that hurt the motor hp more than help it??

Re: Exhaust size
 

2 1/4 into 40s sounds great!

Re: Exhaust size
 

On my 73 BBC I have Long Tube headers to a stainless summit X-pipe to 3" pipe I cant remember what series of flowmasters to 4 inch tips dumping right over the rear end, it is actually quiet compared to my 77 SBC that just has 2 1/4 to Flowmasters 40 series to turndowns. The X-pipe quiets it down alot, until the cutouts are off.

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The engine matters as much as the mufflers. I took some 2 chamber flowmasters off of my 9.5:1 400 sbc because it was too loud and gave them to a friend with a stock bbc and it was quiet

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i have/had a 3" system on my stock bolt-ons only crate 350 and i KNOW i lost some torque. you need to be putting out some power to run 3" all the way back in my opinion...

Re: Exhaust size
 

So what would everyone recommend for a pretty much stock 454? 2 1/4, 3?

I believe it has 3 on it now but the pipe is in bad shape and has glasspacks that dump right before the rear axle. Hate the sound of it :\

Re: Exhaust size
 

Most stock 454's seem to come from the factory with a 2.5" system. If you're staying stock and running duals go with 2.5, high flow mufflers and run the exhaust over the rear axle. Dumping exhaust gases under the truck isn't a sound practice IMO.

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How will the 2.5 do with a smaller 350 motor is the question now. Plan is to ditch this 454 sooner rather then later but I obviously need an exhaust system until I do that.

I agree that dumping under the truck isn't a good idea but that's how the truck came and its on my fix list :)

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Dual 2.5" on a stock/mild 350 is good, I ran dual 3" and lost power, but gained a great sound.

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I had 2.5" dual run into 3" mufflers. sounded damn near the same as 3" run into the same mufflers. Just not quite as loud.

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3 in collecter from headers > to 3 in high flow cat > to one flowmaster ( don't know what sereies) 2 2.5 pipes coming out . sounds & performs great . there is something to overkill on to big an exhaust . I would say unless yoiu have 500 plus horses , stay with 2.4-2.5 out the back .

Oh , 408 warmed up , but nothing crazy

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I'm running 3" duals into super 44's dumped under the bed. I won't be sneaking up on anybody, that's for sure.;)

Re: Exhaust size
 

Ran 2.5 with 40 series flowmasters on my 350 and didn't change any thing when I went to the 454. Just had to shorten the pipe due to long tube headers but the setup sounds great on both motors

You cant compare a 4 banger to a big block. My Accord also has 2.5 from header back with a 40 series and it is much louder than the truck.