shaks 442 clone

Do you think that will be a good exhaust choice for a 455?

the mufflers will be 40 series flowmasters i already have them.

dar83501

headers to straight pipe man, headers to straight pipe.

Rallye469

Nothing wrong with an x-pipe, wish I had installed one.
But 3" exhaust seems excessive.
It's money that won't show a return over 2.5" exhaust.
-Pete

joe_padavano

I strongly agree that for a mild 455, 2.5" should be fine. 3" won't hurt anything, but you'll spend more money and have less clearance over the axle. The X-pipe is a very good idea.

Oldsguy

I say go with 2.5" pipe, fits better.

shaks 442 clone

i dont plan on running tailpipes

currently the car has dual 2 1/4 exhaust with cherry bomb straight throughs that dump a few inches before the axle and i plan on doing the same this if i can with the new exhaust setup

kaz442

I'm running pypes complete(tail pipes also) 3" set up with the X and dumps. This is on a 490 stroker BBO I have run it with the open exhaust and with it closed and have seen no difference in ET or miles per hour. The X does make it a little quieter, helps at the track when they have a noise limit.
The hole set up with hangers and band clamps was $650. Jkaz

gumbyssfakee

i would go with the 2.5 just for clearance issues. i have a 2.5 with a h-pipe and it touches the drivetrain when the car is on a lift but once on the ground everything is all clear. and besides 2.5 is plenty.

shaks 442 clone

an x pipe quiets the exhaust down? really?

Oldsguy

The way it has been explained to me is this. It is all about waves of pressure (sound) passing down the pipe, through the muffler (if applicable) and out the tailpipe. Without an X or H pipe, each tailpipe has four waves of sound exiting for a given amount of time. With the X or H pipe, each tailpipe has eight waves of sound exiting for a given amount of time....divided by two. The total amount of sound may be the same because there are two pipes but with twice the sound waves traveling down each pipe there is a cancellation effect. I am not a sound engineer nor do I begin to understand all the mathematics involved in effective exhaust systems. I guess it sort of "smooths out" the total sound of the exhaust. Conversely, if you have ever heard an engine with zoomies each pipe seems to be so loud because the sound is so staccato in quality, of course they are only about 18 inches long too, I guess that helps. Does all this sound weird? Maybe I shouldn't post this. Somebody save me.......

By the way, I had 3" pipes through shorty mufflers dumping in front of the rear axle on the 455 in my 1969 Delta. They were probably too big, I know they were too big to pass over the axle and exit under the bumper. That is why the dumped in front of the axle.

joe_padavano

The X-pipe helps by allowing each exhaust pulse to "see" both mufflers, so you've effectively cut the muffler backpressure in half. Since the pulse pressure is also split between the two mufflers, you also reduce the sound level. I will caution that ending the exhaust in front of the axle has some problems. First, you're increasing the chances of an exhaust leak getting into the passenger compartment. Second, even if you don't have a leak, the extra heat of the exhaust in the rear axle cavity can accelerate the aging of rubber tubing on the fuel and brake lines (been there, got the t-shirt). Finally, I found that the exhaust noise resonated in the rear axle cavity, making the droning sound even worse at freeway speeds.

Oldsguy

Whew, Saved. I can attest to the fact about the sound resonating at highway speeds.

Rallye469

I second that.
I had to cut my tail pipes to actually make room for 325's.
Worst mistake I've made. The sound of my exhaust in the cabin
is annoyingly loud. Even though outside the car it's quieter!

shaks 442 clone

I don't know if you guys are aware but im 19 years old turning 20 in May and this is the time for me to have a loud muscle car haha.

J-(Chicago)

You will like the loud exhaust, but not the droning.
I'd run open headers before I stopped a pipe before the rear axle again. It was awful, especially in a car with no interior and rotten rear floors. Couldn't hear or breathe Even though it dumped out 90 past the door before the wheel. Didn't make much difference.
It lasted 2 days before I re ran it.
Stick your head in a big stereo speaker box with some Wu Tang playing and that's how your driving experience will be.

joe_padavano

I'm approaching the 30th anniversary of my 20th birthday, also in May (do the math).

I will admit that things that didn't bother me three decades ago now irritate me (used to be the first thing I did when getting a car was to rip out that heavy A/C - now I'm putting them in...). For example, I'll take Dynomax mufflers over those obnoxious Flowmasters any day (plus, the Dynomax has less backpressure!). Having said that, I'll second the response above - it's not the volume that's the problem, it's the droning that will drive you crazy. I was about 25 when I ran this setup and even then it bothered me.

Oldsguy

Wu Tang!!???? Eoooowww!

Run to Rund

The resonance through the body from dumping exhaust before the rear axle gets annoying and will tire you, even though you might not notice it. Loud is better achieved with bigger diameter pipes and the right mufflers, along with "enough" camshaft. Try Walker 21468 3" diesel truck mufflers. They are straight through, perforated core (louvered cores cost flow), no HP loss, significant noise reduction vs. open headers. Still fairly loud especially when you get on it. I am running 3" exhaust after headers, and 3" Torque Tech tailpipes.

shaks 442 clone

I had hooker long tuber headers going into 2 1/4 piping into cherry bomb glass pack mufflers that dumped before the axle i kinda loved it haha

so i think i can live with the dronning

Redog

X pipe FTW.

Have one on the Delta and I love it

shaks 442 clone

did u have it made by the exhaust shop or did you buy it pre made?