Are cast iron manifolds that much more quiet than headers?

[HeavyHauler]

I dont think that I have ever owned a car with cast iron manifolds before. Will the cast iron manifolds be all that much more quiet than a set of headers if you are running the exact same mufflers for instance a set of flowmaster 40 series?

[hamjet]

In my experience, yes. I don't know it sandersons are quieter than cheaper headers though.

[truckster]

Yes, especially in the firewall area and under the front - inside the vehicle.

[RustyBucket]

I don't find any difference at the exit end of the exhaust system.

[jocko]

Agree with all - the additional noise (or music, take your pick) from headers really just manifests in the cab, not out the back. The cab noise isn’t really musical though on a long trip.

[Stocker]

Originally Posted by jocko

Agree with all - the additional noise (or music, take your pick) from headers really just manifests in the cab, not out the back. The cab noise isn’t really musical though on a long trip.

That depends. When I was 19 I had a '65 Corvette with the 365HP engine (solid lifters, same engine as FI except for the carb). I put a set of Hooker headers on it. My job involved travelling, sometimes hundreds of miles between assignments. I loved the sound, even on long trips. Being 19 may have influenced my thinking.

To the OP, yeah, like others said, cast manifolds are noticeably quieter from inside the cab.

[LS short box]

If you are running 40 series Flow Masters the truck will be a bit loud matter what.

[jocko]

Originally Posted by Stocker

That depends. When I was 19 I had a '65 Corvette with the 365HP engine (solid lifters, same engine as FI except for the carb). I put a set of Hooker headers on it. My job involved travelling, sometimes hundreds of miles between assignments. I loved the sound, even on long trips. Being 19 may have influenced my thinking.

Excellent point - perspective is indeed age-dependent. At 19, I had a tunnel-rammed 327 with headers and bolt on cherry bomb header "mufflers" that essentially ended right under my seat on a 57 bel air. I might be almost deaf now, but it sure sounded good back then

[HeavyHauler]

Originally Posted by LS short box

If you are running 40 series Flow Masters the truck will be a bit loud matter what.

Yes we all know that. I have never had any of my classic cars that had stock exhaust manifolds. Only headers with some type of performance muffler.....like flowmasters.

[57taskforce]

Originally Posted by jocko

Excellent point - perspective is indeed age-dependent. At 19, I had a tunnel-rammed 327 with headers and bolt on cherry bomb header "mufflers" that essentially ended right under my seat on a 57 bel air. I might be almost deaf now, but it sure sounded good back then

Sounds bad ass to me... at 32 I guess I’m still young though....

[Stocker]

A bit off topic but while we're talking about noise I gotta add this:

1968, same '65 Corvette, 19 years old, working in Barstow California. Went to a friend's place near Fresno on a weekend and we installed the Hooker headers. Started Saturday, finished Sunday except for welding the reducers to the exhaust pipes. Couldn't find anyone to do it so I drove it back to Barstow with open headers dumping right near my feet. It was about 240 miles, through Bakersfield and across the desert, and I'll never forget that glorious sound!!

If I did that now, I would probably 1) Get a ticket -- or several, and 2) get a throbbing headache.

[jocko]

Originally Posted by 57taskforce

Sounds bad ass to me... at 32 I guess I’m still young though....

It was, or at least I thought it was back in the day anyway, ha Let's just say I was on a first name basis with every gas station attendant.. The only thing louder than the exhaust was the pj gear drive. I bet my neighbors hated me. I wonder where it is now. Sorry to hijack HeavyHauler, I'm gettin all misty in my old age.

[Ol Blue K20]

I love my headers, I really don't notice in the cab a lot. If I open the go fast pedal is when I notice it. The big block sounds great through the flowmasters.....

[garyd1961]

I open the back glass so I can hear my pipes, lol.

[special-K]

I guess my ears are different. I never noticed headers making my trucks any louder in the cab. I mean louder? Nope, never in one of my trucks. I'm not saying there might not be added low level sound due to the tubes vs cast, but nothing worth noting. Nothing to affect a reason the run headers or not. I had brand new custom dual exhaust put on my '71 Custom Camper before taking it from Maryland to Arizona for a vacation. Descending from the North Rim of Grand Canyon one manifold blew out. We couldn't find a manifold so they put a set of cheap headers on. They had no effect on the sound level in the cab. We were able to enjoy our conversations just the same as before for thousands more miles of hiway driving. What I hear in my trucks is out behind the cab. In that truck I loved the sound of the pipes through the open slider and the two rearward side camper windows I'd leave cranked out a bit. Especially running it out the merge ramp after a stop. But that steady purr at hiway speed was music to my ears

I never know what people mean by loud in the cab. I must be half deaf. I have two videos that show what my truck sounds like at idle and taking off easy, and one on the pedal. I've played them here before. I might be missing this noise and need to have it pointed out to me

[mr.precision]

Depends a lot on the motor, of course.
Under hood and in cab noise is generally greater with headers.
Out the back is the same.
My 2 cents based on numerous trucks owned over the years.

[57taskforce]

Originally Posted by jocko

It was, or at least I thought it was back in the day anyway, ha Let's just say I was on a first name basis with every gas station attendant.. The only thing louder than the exhaust was the pj gear drive. I bet my neighbors hated me. I wonder where it is now. Sorry to hijack HeavyHauler, I'm gettin all misty in my old age.

Man that is a pretty setup! I bet that was a blast to drive.

[custom10nut]

There’s pros and cons to both.
Cast iron pros: quieter, and less under hood heat.
Cons: 2 inch outlets and more constricted primary tubes.
Headers
Pros: many options for primary tube and collector sizes,
Cons: they cast off a lot of heat and create more noise resonance in the cab.
For me the biggest con, is that the collector is right next to the starter and heat soak will fry the starter quickly, if you don’t put a heat blanket on it.
At the exhaust tip end they’re about the same, as the muffler flow will determine that sound.
I think if someone made a Rams Horn cast iron manifold, with 2 1/2 inch collectors, I’d put them on it a heartbeat.

[Stocker]

Something just now came to mind (1968 was a long time ago & my memory ain't what it should be). A good part of the extra noise (a very good part) from headers in my old Corvette came from the solid lifters.
I still appreciate that light, rapid clatter, like mice tap-dancing on the valve covers.

[truckster]

Originally Posted by custom10nut

There’s pros and cons to both.
Cast iron pros: quieter, and less under hood heat.
Cons: 2 inch outlets and more constricted primary tubes.
Headers
Pros: many options for primary tube and collector sizes,
Cons: they cast off a lot of heat and create more noise resonance in the cab.
For me the biggest con, is that the collector is right next to the starter and heat soak will fry the starter quickly, if you don’t put a heat blanket on it.
At the exhaust tip end they’re about the same, as the muffler flow will determine that sound.
I think if someone made a Rams Horn cast iron manifold, with 2 1/2 inch collectors, I’d put them on it a heartbeat.

I got mine from Speedway. I think others make them without the brackets.

https://www.speedwaymotors.com/Corve...fold,9133.html