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Exhaust decissions

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big_truxx

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I want to redo my dd's exhaust and I have some questions.

What is a good size pipe to run for a 350? Is 3" too big? Is 2.5" better?
 
I think 2.5 is plenty if you're running duals. You've gotta keep in mind that volume increases exponentially with diameter increases.

2.25" = 3.97"sq
2.5" = 4.9"sq
3" = 7.07 "sq

You can see how drastic a difference there is. As 2.5 would be sufficient, 3 would be approaching excessive IMO.
 
dual 2.5

single 3"


I have a single 3".... alot louder than a dual system seeing as i live in cali where 2 cats are required for dual exhaust
 
On near stock engines a 2.0" dual setup is fine, when you start getting up around 400hp then you wanna open em up to 2.5".

if you wanna bump up the bottom end w/o hurting the top then install a crossover pipe between the collectors and mufflers, mine is directly behind the transfer case.

a crossover pipe will also smooth out the exhaust pulses, even with #40 2.5' flowmasters and duals exiting behind each rear tire my exhaust note is off the chain and very loud when the power starts building (you outta hear those pipes ring) , probably need some resonators.
 
sorry to hijack but i need some help to. i currently have the stock exhaust and exhaust manifold apart from a flowmaster delta flow muffler. Im going to go ahead and get a new system in a week or so. This is my plan as of now. Flowtech afterburner headers, magnaflow x pipe 2.25's. 2 flowmaster super 40's both 2.25s and both exiting just behind the rear wheels. and new pipes as mine are rusting away. I know the flowtechs arent the greatest but i can get a set cheap if im quick about it. if anyone wants to know what engine mods its a 350 with a crosswind manifold, K&N filter, K&N xstream lid, and a edlebrock 650 thunder series carb. what do you all think? anything you would change.
 
sounds fine...

you'll see why the afterburners are so cheap when you get your hands on em... they'll make power just fine but the quality of the welds, inside and out along with a coating that comes off when you breath on it makes them hard to look at after a while.
 
i know this is a really stupid question but are there any other "cheaper" headers you suggest? im really scraping for money for my truck right now but i guess like all you im pretty addicted to it. also im not really interested on the visual of my headers i just dont want leaks or problems along the way.
 
I don't want to keep takin this thread OT but afterburners are good headers if your looking for power... underhood temps and fitting them can be a problem tho... my coating came off after 2 starts of a brand new 355 and i also had to grind the frame about 1/4 inch to get them to fit.... i would have bent them but the y pipe wouldn't have fit. I Like the sound tho.... sounds damn good with a 3 inch single and a generic flowmaster.

dyno max makes a good header for about 250 but they're ceramic coated so 250 is a good deal...

As far as leaks go, red rtv on the header or gaskets is supposed to seal them up tight.
 
ok dual 2.5" is settled then :D :waytogo: already ruinning 2.25" duals w/ stupid glasspacks and no turn downs :haha: I'm sure the new system I build from parts from summit will be much better. I will not need an xover it's just my DD 82 crew dually ;) I always thought 2.5" max on SBC and use 3" on BBC :waytogo: Was really trying to confirm my opin by other people's :D
 
On my old '79 I ran dual 2.5 w/ an H-pipe and a pair of Dynomax Thrush mufflers - it sounded great! The H-pipe made all the difference in the world with sound.

Though I think dual 2.5" was too big for a stock 350 w/ and edelbrock top end.. I doubt I was even pushing 275hp out of it
 
Don't get the flowtechs man.......Hedman or Hooker competition hedders,
those are my 2 choices
do you see anybody in the know running flowtechs...?
me either.!
 
ok i guess i should have known better to buy the cheap option, but............. what are the summit headers like part no. SUM-G9006-9 . i know they are still cheap but are ceramic coated and summit have always been pretty reliable in my past expierience with them.
 
Exhaust

"Dynomax Thrush mufflers" I have heard good things about these... From the 350 I run hookers to glasspacks out the sides in front of the rear tires.. I was thinking of upgrading myself... the glasspacks were cheap but it is time for an upgrade... Let us know what you decide to run..
 
stus84 said:
"Dynomax Thrush mufflers"
Click to expand...

I was running Assmaster 40 series w/out an H-pipe and it sounded HORRIBLE.

I was very happy when I went to the Thrush's & H-Pipe over the 40's, and sold the used Assmasters for more than I paid for the thrushs :)
 
not sure who makes the headers on my 75 but that has full length headers and flowmasters I believe they are 40's and it sounds good w/o xover :dunno: also has a mild cam in the 350 :D
 
76blazerguy said:
ok i guess i should have known better to buy the cheap option, but............. what are the summit headers like part no. SUM-G9006-9 . i know they are still cheap but are ceramic coated and summit have always been pretty reliable in my past expierience with them.
Click to expand...


I have the same set, uncoated... I wish I had gotten them coated, cuz they are fricken HOT... otherwise, good all around header...
 
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