[Crunge98]

I'm trying to figure out what exhaust I want to run on my 72 Chevelle. I have read many posts, but everyone has different engine combinations. The engine is a 70 454 and I swapped out the pistons for forged flat tops and bored it 0.030 over. I am going to run the stock heads and intake. The carb I will buy a new one sized to the engine. I haven't picked out a cam yet, but I want to stay stock or just a hair bigger. Anyone recommend a good long tube ceramic coated header that fits the car nice and what size header pipes would you recommend? What about the exhaust size from the header to the mufflers and tail pipe size? H or X pipe? What about muffler size. I want some exhaust noise but not too much. I want a good exhaust system that will fit up nice to the car and the headers with minimal modifications.

Thanks for the help.

Jay

 

[weidhopper]

I have Hooker ceramic coated Super Comps on my 427 with a Pypes 2 1/2" system all the way out the back I was real happy with the way it fit. I have the Race Pro mufflers and with the X pipe it had a nice muscle car idle and at cruising speeds it was really quiet in the car. I took the X pipe out of my car to hear more of the cam at an idle and I can't believe how much louder the car is going down the road.

 

[BB68]

I have 2" Hooker comp that I clearanced then sent out to jethot. From there it goes into 3" pypes X, thru to 3" race flo mufflers(i think been a long time, but they are big case with straight thru flow - glass pack), exiting out 2.5" pypes tails. This is has a nice note but is extremely quiet going down the road. Wife likes it. For example its quieter than a late model pickup with dual exhaust. If I feel the need to hear it I uncap the cutouts

 

[427L88]

I also have the 2" Hooker headers, but here I'dd recommend the smaller tubed Hedman's with the 3" collector. You'll appreciate the lower peak header TQ. At your power level 2.5" head pipes on back would be fine. Bigger case mufflers are quieter. Once again, at your power level baffled mufflers are OK, you arent obliged to run straight thru type. They do have different sounds, and that's your ear's choice.

 

[CMCE]

With your engine specs and intended use, it's important that you avoid going too big with exhaust size. 2.5" is as big as you need. Anything bigger at your HP level reduces exhaust gas velocity and therefore torque. As far as system recomendations, pick the type of system based on your needs and then pick your muffler based on the db level and tone you want.
X-Pipe: This will give you a slight bump in high RPM HP without reducing low end torque. It will also reduce db levels considerably BUT smooth out the sound, especially on an engine with a stock-ish cam. Some people don't like the sound and you need to be realistic about your intended use and whether you'll ever benefit from it HP wise.
H-Pipe: This will add slight bottom end torque without reducing high RPM HP. It will not affect tone and only slightly reduce db levels.
Straight Duals: Self explanatory.
As far as mufflers are concerned, you need to choose the sound level you want. General rule of thumb- Chambered are the loudest, Turbo's are the quietest, and straight-through's are in the middle. You need to take your final drive ratio in top gear into consideration- If your cruise rpm is between +/- 1600-2400 rpm you will be susceptible to drone. Chambered are the biggest offenders, then come straight-throughs, and Turbo's do the best job but no guarantee. Check out some sound clips here or give us a call. Happy to talk to you.

 

[65cayne]

With your engine specs and intended use, it's important that you avoid going too big with exhaust size. 2.5" is as big as you need. Anything bigger at your HP level reduces exhaust gas velocity and therefore torque. As far as system recomendations, pick the type of system based on your needs and then pick your muffler based on the db level and tone you want.
X-Pipe: This will give you a slight bump in high RPM HP without reducing low end torque. It will also reduce db levels considerably BUT smooth out the sound, especially on an engine with a stock-ish cam. Some people don't like the sound and you need to be realistic about your intended use and whether you'll ever benefit from it HP wise.
H-Pipe: This will add slight bottom end torque without reducing high RPM HP. It will not affect tone and only slightly reduce db levels.
Straight Duals: Self explanatory.
As far as mufflers are concerned, you need to choose the sound level you want. General rule of thumb- Chambered are the loudest, Turbo's are the quietest, and straight-through's are in the middle. You need to take your final drive ratio in top gear into consideration- If your cruise rpm is between +/- 1600-2400 rpm you will susceptable to drone. Chambered are the biggest offenders, then come straight-throughs, and Turbo's do the best job but no guarantee. Check out some sound clips here or give us a call. Happy to talk to you.

Just my experience... my straight through mufflers are way louder than my chambered flowmasters

 

[overdriv]

I have Hedman Elite ceramic coated. Very nice looking and they fit well.
Then I hae a flow master 2.5” exhaust all the way to rear bumper. The exhaust kit came with super 44s and they are loud. I now have dynamax mufflers which are much more quiet but are loud when I stand on it.

 

[CMCE]

Just my experience... my straight through mufflers are way louder than my chambered flowmasters

Yeah each type of muffler covers a broad spectrum of designs so nothing is written in stone as to what type is quieter than another. FM 40’s is what most people associate with noise and drone, yet their 70 series addresses both of those issues and can be quieter than a lot of straight throughs and even some turbo mufflers.
The noise level of straight through’s depends on the size and amount of holes in the pipe, and more importantly the length of the muffler. It is almost impossible to predict exactly what a muffler will sound like with different engine combinations.
I often tell my customers that if you have a street driven car your best bet for satisfaction is a turbo muffler. It’s a good compromise between noise/drone/tone and flow.

 

[wes migletz]

What effect would a 2 1/2 “ resonator have on noise? For our 70 2wd K5, I went with 2 1/2” Vibrant resonators and large case 2 1/2” Dynomax Ultraflows and a crossover pipe. The guy who did the exhaust had fun getting it to fit, with the 31 gallon gas tank we used… It will be behind a mildly cammed L92 with a ZL1 blower, backed by a 6L90 and a 3.42 rear and a 235/75 R15 tire.

I have the same resonator/muffler combo for my 67 SWB with a low-horse SBC, backed by a 700R4 and 3.73 gear with a 235/75 R15 tire.

Unfortunately, I’m a few months away from getting either vehicle running, but I am curious about how they will sound. I do not want a loud, or droning exhaust at freeway speeds.

 

[mrpaticular]

Ceramic coated is a must for looks and heat. 1 3/4 - 1 7/8 primary tubes with a shorter collector. Smaller primaries for steering link clearance and shorter collectors to keep you from buying an aftermarket trans crossmember.
3'" to the muffler and 2.5 out the back. A full 3" will double the noise of a 2.5.
Rick

 

[Crunge98]

Thanks everyone this is good information. I have been a small block guy for many years and moving up to a big block I'm starting back at square one. I figured do as much research and figuring before I spend the money.

@overdriv are those long tube headers and did you do any modifications to the car?

 

[confused]

All of my big block mopars get 1 7/8 headers with 3" to the x pipe then full 2.5 out the back.I prefer Dynomax Super Turbo mufflers with the longest case available.
My 454 truck will have 1 3/4 ceramic long tubes with a full 2.5 exhaust.Likely going to run magnaflow or borla (I have both already) and may put some super turbos under the bed before the bumper to quiet it down to sleeper status.
I prefer Dr. Gas for my x pipe but they seem to be out of business.

 

[overdriv]

They are long tube headers and the collector has ball and socket type flange, which does not use gaskets and does not leak.
I did not modify the car or the headers for installation. I did have to take the bolt out of the left motor mount to install the left header.

 

[Crunge98]

Ok cool I have the body off, and engine is on the stand so I will install them when the engine goes in.

 

[ekitch]

I have hedman ceramic coated headers on my 454, they fit nice. The header back is a magnaflow stainless steel 3" exhaust with an X pipe. Sounds great at idle and insane at full throttle but it has that dreaded drone around 2000 rpm or so. It is really annoying. Was thinking about changing the mufflers out for some flowmaster delta 50's or maybe superturbos.

 

['70basketcase]

for a slightly modded 454 street driven , 1 3/4" headers, 3" collectors down to 2 1/2" pipes, H-pipe ( more oldschool sound than X pipes), Aluminized mandrel bent 2 1/2" pipes with tail pipes , Dynomax Super Turbo mufflers..

Quiet when you need it, nice sound when you floor it, does not break the bank, and Super Turbos are some fo the best flowing quiet muffs on the market, 1 3/4 headers wont be loud, easier ton install and change plugs than 2" primaries, and stretch low to midrange torque...

Peter

 

[The Camaro Guy]

I have a local shop install the pipes, around $150. X pipe with 2.5 aluminized. The latest one I used Flomast FX polished turbos, sounds a lot like a Magnaflow, Cost is $40 from Holley. Dynaflow headers.

 

[oldguy67]

for a slightly modded 454 street driven , 1 3/4" headers, 3" collectors down to 2 1/2" pipes, H-pipe ( more oldschool sound than X pipes), Aluminized mandrel bent 2 1/2" pipes with tail pipes , Dynomax Super Turbo mufflers..

Quiet when you need it, nice sound when you floor it, does not break the bank, and Super Turbos are some fo the best flowing quiet muffs on the market, 1 3/4 headers wont be loud, easier ton install and change plugs than 2" primaries, and stretch low to midrange torque...

Peter

X-2 big time