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Discussion Starter · #1 ·
My new 55 has 2 1/4" pipes. Will this be large enough If I decide to put the LS2 in it? The pipes look to be in great shape. The mufflers are 14" Super Turbos and too loud inside the car and shorty headers. All out the back.. Hope to decide on the LS2 soon. The 350, t400 with 5k miles may have to come out.
 

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Mickey is right it will run. It could lead to higher temps under the floor at the mufflers if you get on it a lot and will reduce power. And if its regular bent pipe it will have kinks in it and that will reduce flow the is even more on that size pipe.

I would just do it right min dual 2.5" with a cross over or x pipe close to the motor. And i would get it mandrel bent as they will be true size no kinks. Since the mufflers you have now are bad. I would look or run a set of magnaflows.

One think to note we had a dyno day for our local car club and a stock ls2 with a tune made 360hp at the rears! A "built" 350 in a nova made 210hp lol. The owner was pissed. Hard to beat a stock LS motor for power!
 

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I used....

PYPES. They have a stainless 2.5" system that fits the 55
 

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Discussion Starter · #5 ·
Thanks that is what I thought . I know it needs new mufflers but they would be 2.25". I do not want to buy them until I decide if the LS2 is going in or not.
The first 55 has a little smoke puffing from one bank. And I had the LS2 so that was an easy decision. But this 5K mile motor is a other story. It looks good and runs good with no issues. It is a great problem.
:sign0020:
 

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I had a 4.8 swapped to a 6.0 in a Silverado with long tubes and 2.5" pipes with a crossover muffler, so it was true dual. It was too loud and I put on a resonator to try to tame it. The exhaust guy said that 2.5 was a bit loud and really only necessary if you are making north of 500 horse. The pipes exited out the rear tucked under the bumper, so maybe that had something to do with it. I plan on going 2.25 with my wife's 5.3. I've gone big twice and regretted it. I remember seeing a Flowmaster muffler on TV that had a valve that opened at WOT like some Corvettes have and that caught my attention. The "right" sound is very much a personal opinion, so your mileage may vary. How much sound proofing you have done to the interior will also have a huge effect.
 

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Muffler selection plays the biggest factor noise wise. El cheapo cherry bombs will sound like crap. a good exahaust. guy knows how to set a car up to not sound like poop and still make power. Ie he will give you the best sounding and performing options price and performance wise. There are a lot of exhaust shops that are horrible at anything but putting a replacement muffler on they give bad advice and just waste people's money.
I am lucky to have a very good friend that owns a exhaust shop. He also just installed a dyno jet. So he gets a before and after hp number all be it he does charge for the dyno run.

A 5.3 would be fine with dual 2.25". As. most stock applications are that into the muffler and 2.75 single out the back anyway. A Ls2 really needs 2.5" Just get the right muffler and it will keep it quite. after all the stock c6 is dual 2.5" they are not loud at all. So one is really hurting performance with 2.25" on a 6.0 or bigger IMO.
 

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Guys these motors are not like the sbc they like to breath air and air out equal power. The 5.3 stock is 300hp easily. So like I said anything larger than a 5.3 you really want dual 2.5". If it was me in a Trifive with room to work why limit yourself. One might find a cheap long block 6.0 which will bolt right in place of the 5.3. Now you have smallish exhaust and will want more out of it
 

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Stock 4.8 with headers

When I purchased my 55 wagon, it had stock exhaust maifolds into 2 1/4 pipes with Magnaflows straight out back. There was no cross over or X pipe. I would like to keep the Magnaflows and run the exhaust behind the rear wheel with a turn down. My question is: How important is a cross over/ X pipe? Should I run 2.5 pipes? Down the road, I may do a cam swap and a manifold. Thanks in advance
 
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My new 55 has 2 1/4" pipes. Will this be large enough If I decide to put the LS2 in it?
We almost met at Memphis. Seems you want to build Your driver. JMHO, the 2 1/2 " do wonderful. Your choice of mufflers. I love the sound of 3", 24" glass packs (not the loud Cherry Bombs). Just my style. Lloyd :bowtier:
 

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Discussion Starter · #13 ·
I have been putting more time into my first 55 to sell it . It is gone now so I am ready to start on the newest one. I found MOST of the noise is from loose bolts on the headers and colector to exhaust pipe. everything looks new but the turbos are to small. Need to be at least 21". sounds much better but likely need new gaskets at header and collector. For now that is improved. So if the ls2 is going in I will get a 2.5" or 3" kit. Loyd do you have a good blow up quality picture of your stock 265 from over head? I want to add a stock engine compartment picture to my display (if the ls2 goes in.)
 

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When I purchased my 55 wagon, it had stock exhaust maifolds into 2 1/4 pipes with Magnaflows straight out back. There was no cross over or X pipe. I would like to keep the Magnaflows and run the exhaust behind the rear wheel with a turn down. My question is: How important is a cross over/ X pipe? Should I run 2.5 pipes? Down the road, I may do a cam swap and a manifold. Thanks in advance
What size are the Magnaflows in/out? If they are 2.5'' and just necked down then run a 2.5''. If they are 2.25'' then they will be the restriction if you swap to a full 2.5'' and your not gaining alot. You can look at the mufflers and easily ID what size they are. As the in/out will be 2.5'' with a neck down.
 

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Flowmaster with valve by Snappy

earlier in this Thread Member "Snappy" noted "I remember seeing a Flowmaster muffler on TV that had a valve that opened at WOT like some Corvettes have and that caught my attention." Has anyone seen a muffer like this? I have not, but it sounds interesting.
 

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earlier in this Thread Member "Snappy" noted "I remember seeing a Flowmaster muffler on TV that had a valve that opened at WOT like some Corvettes have and that caught my attention." Has anyone seen a muffer like this? I have not, but it sounds interesting.

Have not seen this type.......:anim_25:
:gba:
bowtie-trifive
 
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