OPINIONS ON EXHAUST SOUND

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To be honest, that does look like a Flowmaster, and Flowmaster numbering system is very similar, 5 numbers (or more, for newer delta flow)
But fm's number for that would be 42541 (40 series, 2 1/2 pipe, first 3 digits)
Your says 42451, I suspect a Chinese clone of an FM.
NOT saying a real FM would be quieter or sound better.
331, very good catch. I had not blown up my data to see the two numbers transposed. I bet you are right: Chinese knockoffs. Their patent expired in about 2000 so many have now used the methods and designs they used.

Here is what I am doing. I am building 12 of these VOE mufflers for 70 GTO's. This one is ready to weld. Takes a lot of work to get them to fit just right and for air to pass through them without whistling.

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Power? it doesn't really matter unless you are class racing. ET racing is a dial in. Street performance is limited to how much bite is at the stop light and 300 horse is about enough.

This old car lives at 1/4 throttle. A B body would be nice. I'll keep looking.
 
This old car lives at 1/4 throttle. A B body would be nice. I'll keep looking.
And I bet it's a pleasure to drive. It doesn't need to be quick or loud.
 
@VOETOM, if I may ask, what is your opinion of Magnaflow? I have some looong 3" straight-thru mf's on my Opel. Quiet. I wonder if they are TOO quiet. (22 or 24"case, 28 oal)
I have some 3 1/2 in/out aeros I could use.
Magnaflow work well. in fact in our data set, you see Straightline Performance? Those are Magnaflows. Like XCELERATORs and Dynomax Ultaflows, the Magnaflows with stainless steel aorund the perofmarted tube an ceramic or glass or basalt fiber packing work great and run well.
 
Hi Folks

What are your opinions on this combo?

340 with Comp XE262
Auto Trans with 323 gears
Original TQ carb
1969 HP exhaust manifolds
2 1/2 inch TTI head pipes
2 1/2 inch TTI Exhaust pipes with H pipe
Flowmaster 409S mufflers
2 1/2 inch TTI over axle tail pipes with turn downs.

In a '71 Demon 100% cruiser

What say Ye?
Hey @vynn23 ........If you are gonna' red X my combo, how about a suggestion? :)
 
The XLERATOR is straight through, the Super Turbo is a three pass version, like stock ones are. I'll shoot pictures and share them later.
Tom will the 20” Super Turbo’s fit under a 69 Dart 340 or should I go with the next length shorter ?
 
I used the 2.5" 17748s under my 69 Barracuda BUT I flanged the outputs so I could blt the tailpipes on and not make it so har don the bender at the shop to get the tailpipes just right. I think the 17747s are 2.25" but flanging them will make it easier too.
 
I don't know if it's the firing order, or what, but FLowmasters always sounded really good to me on the Fox body 5.0 Mustangs that got them from the factory. Those sounded really good. Not on much else, though
 
I used the 2.5" 17748s under my 69 Barracuda BUT I flanged the outputs so I could blt the tailpipes on and not make it so har don the bender at the shop to get the tailpipes just right. I think the 17747s are 2.25" but flanging them will make it easier too.
Tom I was about to order the 17748 but I just noticed that Dynomax website says the inlet is Centered and the outlet is Offcenter. My current mufflers are just the opposite, inlet Offcenter and outlet is Centered. I presumes that I may need a new tail pipes made because the mufflers cannot be flipped correct?
 
Tom I was about to order the 17748 but I just noticed that Dynomax website says the inlet is Centered and the outlet is Offcenter. My current mufflers are just the opposite, inlet Offcenter and outlet is Centered. I presumes that I may need a new tail pipes made because the mufflers cannot be flipped correct?
Nick, you can run the UltraFlows in any direction. Just flip them around and you are set!
 
1he 17748s work either direction. They are offset in and center out, typically. Flowmaster types can't be run backwards but most othes straight through or Super Turbo types can. :):)
 
I decided on the XS1256 for my 65 slant 6 car. Seems very nice for the $36 I paid for it on Rockauto!

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I have TTI headers and exhaust with h pipe using dynomax mufflers sound good at idle and when i hit the pedal . No drone at highway speeds . Driving on the highway with the windows closed it is as quiet as any of my new cars , Had flowmasters on the car when I bought it was the first thing to go , driving on the highway was a torture session could not take the drone
Good info, dynomaxs will get my dollar when I am ready for em...
 
I decided on the XS1256 for my 65 slant 6 car. Seems very nice for the $36 Inoaid for it on Rockauto!

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Good choice. Based on a recommendation I read from @VOETOM, I went with dual XS1225’s on my hipo 273. It idles real quiet, but nice throttle response. It’s quieter in the car with this setup than with the slant 6 and leaky stock-ish exhaust I used to have. It’s really been throwing me for a loop.

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Good choice. Based on a recommendation I read from @VOETOM, I went with dual XS1225’s on my hipo 273. It idles real quiet, but nice throttle response. It’s quieter in the car with this setup than with the slant 6 and leaky stock-ish exhaust I used to have. It’s really been throwing me for a loop.

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Love the color man! My car is a black plate car too.

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The welded Flowmaster somethings came off my 76 New Yorker the month I got the car.
Went with Walker Quiet something's. Very happy. No drown. Two cats, two mufflers now.
Power loss? Stock 440, heavy car, who knows.
love the car had a 1975 new yorker what a pleasure to cruise the highways and the 6 dead body trunk was perfect fit 5 pars of skis no problem , wish I still had the car , Even with the smog 440 it would move , not as well as my 70 pimperial but good
 
I’ve been having trouble finding the “right” sound myself. I didn’t like the Flowmaster 40’s. Then I tried the DynoMax Race Bullets, which were actually raspy. So I’m hoping for better luck with these Ultra Flows.

This is on a 3” header back with a 408. Maybe it’s my wide 112 LSA cam with 240/248 duration. Rather mild but it has a small B&M blower on it.

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Race bullets are crazy loud, and I don't care for the sound even on race cars.
Flowmaster 40s are too loud for my taste, and tend to drone. I like my 50 and 70 series big block flowmasters.
I think you will like the ultraflows. Of those three, they would be my choice.
 
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