After talking to Lou at the Mason Dixon race, and reading posts here on the board, I am thinking about removing my dual exhaust (which is in need of repair anyhow) and going to a single pipe system.

Currently I have 2 X 3 into 1 clifford long tube headers that terminate parallel to one another in the vacinity below (and just to the left) the driver's feet.

It is my understanding that running both of these header outlets into a Y that channels into one pipe will improve scavenging. Is that correct?

Some of the questions I have are:

-with the long tube headders do I how far back should I put the Y pipe?
-Is there any particular Y I should use, or is an off the shelf Summit type unit ok?
-Is 2.5 inch the rest of the way back sufficient?

What else am I not thinking of. If you were building this, how would you do it?

Thanks guys,

CE

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-76 Cordoba, 360 4bbl
-68 Valiant, 273 2bbl
-67 Dart /6 4bbl, Leaning Tower of Power!!!

I would go 2" primary pipes into a Flowmaster or Magnaflow Y with the Y junction about 6" behind the trans X-member, then single 2.5" out the back with a Dynomax Super Turbo or similar muffler. Flowmasters are too loud/boomy for me, but I've had good luck with Super Turbo and Thrush turbo muffs. This will handle plenty of power (at least 250 crank HP), and is a great mix of sound, HP, and driveability.

Lou

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Home of Slant6-powered fun machines since 1988

A minimum of 12" after the collectors for the most torque. Don't go below 2.25" for the tail pipe.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Lou,

so something like:

http://www.summitracing.com/parts/FLO-Y ... mage=large

or

http://www.summitracing.com/parts/MPE-1 ... mage=large

With the convergence point 6" behind the tranny mount ?

Personally I think the flowmaster looks much nicer of the two.

On your previous recommendation I am going to go with the Dyno Super Turbo muffler too.


What is the piece/fitting with the "flange" on it that bolts to the header collector called? Might as well order 'em at the same time.

Thanks!

_________________
-76 Cordoba, 360 4bbl
-68 Valiant, 273 2bbl
-67 Dart /6 4bbl, Leaning Tower of Power!!!

Also,

Anyone have experience with the "butt joint" or "V joint" exhaust clamps?

I want to be ablt to remove this exhaust system easily any time I want to.

Thanks,

C

_________________
-76 Cordoba, 360 4bbl
-68 Valiant, 273 2bbl
-67 Dart /6 4bbl, Leaning Tower of Power!!!

Chris,

I haven't used those clamps.

Yep, the flowmaster Y is the one I like. Probably worth the $13 more.

You are looking for header "collectors" that bolt to the header. Most shops will not have the 2.5" collectors. Summit has the flo tech ones with an O2 sensor bung (he said bung) in one of them, which I recommend having at some point. I just ordered a set for spares. You can get 2.5" header flange to 2" pipe off the Summit shelf for about $28/pr. With no O2 bung (he said it again), they are $20/pr.

Lou

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Home of Slant6-powered fun machines since 1988

Lou that begs another question

would there be any advantge to having a bung (heh, heh I said it too) in both of the collectors? Or is having one collector set up sufficient?

I definitely want to have this option for tuning purposes at some point.

Thanks,

CE

_________________
-76 Cordoba, 360 4bbl
-68 Valiant, 273 2bbl
-67 Dart /6 4bbl, Leaning Tower of Power!!!

I put my bung three inches back from where my y meets,,,that sure reads funny,Guzzi Mark

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-76 Cordoba, 360 4bbl
-68 Valiant, 273 2bbl
-67 Dart /6 4bbl, Leaning Tower of Power!!!

I really don't think 2 are needed, although I guess it could help diagnose problems.

Lou

_________________
Home of Slant6-powered fun machines since 1988

This looks similar to what I want to have done... I wonder if I should just get a y-pipe and bring it into a shop? I initially just thought of rolling up and getting an esitimate and seeing what happens...

I have Cliffords on my Slant, longies (the only ones that fit pre-A body 1st gen Valiants afaik), that run into a dual exhaust, 2.25" into Flowmaster 40's. I want to reduce to a single exhaust to reduce overall sound output (I roll into the neighborhood late sometimes, and leave early in the AM at times as well). I would think a 2.25-2.25-into-2.5 would get the job done, right? Then 2.25 all the way back? I don't think anyone makes a 2-2-into-2.25 y pipe do they?

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-Anthony
1962 Plymouth Valiant Signet 200

Here is an interesting article on exhaust and muffler: http://www.pontiacstreetperformance.com ... haust.html

If you don't have a very built motor, 2.25" back will be fine. Your exh shop can flare pipe to fit into a 2.5" Y exit.

Lou

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Home of Slant6-powered fun machines since 1988

if it were my car, i would come off the headers with 2.25", merge to 2.5", put a 50-series flowmaster(if it fits) and put a 2.25 tailpipe on it. the sound that would come out of it would be perfect, not too loud and nice and quiet on the inside. watch for the burn stripe on the flowmaster and you will know its built right.

zedpapa

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1970 dodge dart w/225 /6 bored .040" over, holley 390cfm w/vac. sec., compcams 252s, clifford shorty headers w/2.5" exhaust w/flowmaster, f-body 11" front discs, aluminum A-833OD, 8 1/4 w/3.21 SG
soon to have 5 gears!!!