New build 454 and the wife hates the exhaust smell

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

A

andybflo

Member
Joined
Aug 13, 2020
Posts
37
Reaction score
68
Location
Western NY
First Name
Andrew
Truck Year
1986
Truck Model
C-10 Silverado
Engine Size
5.3 LM7/4L60E
You really want to eliminate the smell? Put cats on it.

I put cats on my '76 GMC Motorhome, which has a Sniper 2. Have cats on my '63 Impala with a Holley Terminator Stealth. In both cases, I got sick of smelling like, and smelling, exhaust. In those cases, the 455 and 409, respectively, lost zero throttle response, fuel economy, or drivability. I'm out about $600 in total, for both cars (pair of Magnaflow, high-flow cats in each), I can take my wife out for a cruise and neither of us smell like unburned hydrocarbons. It will change your exhaust tone a little. I also run them on my LS Swapped, '86 C10. I've gotten various responses from local inspection stations here in NY as to if I need them on that vehicle or not. Being a heavy-half, in NY, you get told yes and no, depending on who you ask.

My old solid cam C1? That stinks, as it should, but anything where I want to *go* somewhere, in a level of comfort, and get out not smelling like a Mobil station, I stuck cats on. They're not a performance loss anymore, don't weigh much, and are the surest way to eliminate those smells, exactly as they were designed to, for the last 50 years.

Then the Sniper can do as it wishes, and as long as it's not terminally rich, it'll have little effect on the cat.

And, no, I'm not mandated to do so by my state, just choose to solve the problem my wife (and I, as I age) brought to my attention years ago...
 
A

andybflo

Member
Joined
Aug 13, 2020
Posts
37
Reaction score
68
Location
Western NY
First Name
Andrew
Truck Year
1986
Truck Model
C-10 Silverado
Engine Size
5.3 LM7/4L60E
3 Ton said:
Dump the Chinese made Holley crap, some of them work, some do not. Why take the chance.
i had one client that both Mom, Dad, and he installed Holley crap on all 3 trucks. They had to go back to a carb because one would not work right.

BTW I did carburation parts before I retired. Holley went out of business the same time Carter and Rochester were forced out of business. Everything NEW is from China, and its all junk. Any of these names on new carbs are Chinese made. 100%

Where do your tail pipes end up? Blowing exhaust back into he cabin is usually on how far back they go.
You have not stated if its leaking form the pipes OR coming form outside in.
Click to expand...

The last Eddys I installed on a car (a 800 CFM AVS and an 600 or 650 CFM AFB) were cast by Weber in Italy and built in the US. That AVS went through my hands six weeks ago. AFB was mid-summer.

The last Holley I bought, for myself was a 4150HP. That was cast, assembled, and flowed in the US. Beginning of this summer.

Might needles/springs/metering rods/jets/etc be made in Asia? Sure. But tell me what isn't. And, sadly, their machine shops are as good or better than ours right now.

I love me some Qjets, but find me one that wasn't cast four plus decades ago... Most, if not all, are tired. I keep a few around here in great shape, but many are whupped and rebuilt/rebushed by questionable shops during those four decades.

I've never had a FI system not work; even down to the lowly, poorly built, Powerjection I once was silly enough to buy. That was terrible to tune, but worked once you dialed it in. I've installed probably fifteen FiTechs, probably fifty Holleys of various flavors over the years. Had one bad mainboard on a Sniper, but that was easy to diagnose, and Holley second-day-air'd me the replacement board. Had one Atomic EFI I struggled with, but even that ran well, eventually...

Almost every time I've had a non-runner brought to me from a peer or friend, it's fuel system not being sorted out properly. Wiring being a close second.
 
7

77Dmax

Full Access Member
Joined
Nov 10, 2024
Posts
71
Reaction score
140
Location
vt
First Name
Joe
Truck Year
1977
Truck Model
c20
Engine Size
6.6
Are the floors/quarters rotted out?
 
C

chris3353

Junior Member
Joined
Apr 2, 2023
Posts
5
Reaction score
5
Location
idaho
First Name
chris
Truck Year
1989
Truck Model
v2500
Engine Size
350
txaggie said:
Howdy all!

I recently rebuilt an 85 suburban 454 and stripped the factory exhaust off for a hooker black heart 2.5” x pipe dual system. Well, my lovely wife hates the exhaust smell and I was curious if some high flow cats might cut down on it?

Let me know if anyone has any recommendations! 454 bored .030 over, Holley sniper, long tubes, etc.
Click to expand...


Something is not right.

Can you data log with the sniper?
what is the AFR at idle when you smell it?
What is the engine temp?
 
SquareRoot

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
4,230
Reaction score
8,126
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
andybflo said:
You really want to eliminate the smell? Put cats on it.

I put cats on my '76 GMC Motorhome, which has a Sniper 2. Have cats on my '63 Impala with a Holley Terminator Stealth. In both cases, I got sick of smelling like, and smelling, exhaust. In those cases, the 455 and 409, respectively, lost zero throttle response, fuel economy, or drivability. I'm out about $600 in total, for both cars (pair of Magnaflow, high-flow cats in each), I can take my wife out for a cruise and neither of us smell like unburned hydrocarbons. It will change your exhaust tone a little. I also run them on my LS Swapped, '86 C10. I've gotten various responses from local inspection stations here in NY as to if I need them on that vehicle or not. Being a heavy-half, in NY, you get told yes and no, depending on who you ask.

My old solid cam C1? That stinks, as it should, but anything where I want to *go* somewhere, in a level of comfort, and get out not smelling like a Mobil station, I stuck cats on. They're not a performance loss anymore, don't weigh much, and are the surest way to eliminate those smells, exactly as they were designed to, for the last 50 years.

Then the Sniper can do as it wishes, and as long as it's not terminally rich, it'll have little effect on the cat.

And, no, I'm not mandated to do so by my state, just choose to solve the problem my wife (and I, as I age) brought to my attention years ago...
Click to expand...
Excellent writeup. I put the magnaflo cat on mine and it's 95% improved. Zero loss in power.
 
SquareRoot

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
4,230
Reaction score
8,126
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
People tend to think that EFI is precise and therefore there is little to no emissions. Wrong. It's much better than a carb by design but any internal combustion engine produces emissions regardless of the AFR. After putting PF4 on my truck my buddy asked me why it still stunk. I could only stare at him like he was stupid. But, you don't know what you don't know.
 
B

Brads74

Junior Member
Joined
Jan 18, 2023
Posts
2
Reaction score
1
Location
arizona
First Name
brad
Truck Year
1974
Truck Model
gmc c1500
Engine Size
350
Have you done a cost analysis of new exhaust system vs new wife???



Just kidding…
 
GTP51

GTP51

Full Access Member
Joined
Sep 6, 2017
Posts
113
Reaction score
124
Location
Melbourne Australia
First Name
Geoff
Truck Year
1987
Truck Model
R10 Silverado half ton Stepside
Engine Size
355
I have the Sniper on mine and have the same extractors as you (small block 355 worked), I fitted cats and it helped a lot over the previous exhaust system but its still has the fuel smell my exhausts exit just before the rear tyres on each side .At present the fuel table at idle is around 14 to 4.2 and I intend to lean it out to around 14.7. One thing I am dealing with it that where the old fuel vapor return line that went to the charcoal canister is no longer used and it is creating exactly the symptoms you have described, stopped at the lights and smell fuel. My canister return line ( canister has been removed)is running through a catch can with an absorbent sand in it but still fumes like crazy despite the exit line being directed under the truck. Anyway hope this helps although its 2 issues not one. I am thing of using vented fuel caps(duel tanks) and blocking off the canister return line.
cheers
Geoff
 
W

WP29P4A

Full Access Member
Joined
Jul 18, 2021
Posts
890
Reaction score
1,517
Location
Nevada
First Name
Mike
Truck Year
1987
Truck Model
Sierra Classic V1500
Engine Size
350 TBI
Are you sure that what you are smelling is exhaust and not the new coatings and gaskets? When I installed the new exhaust system on our 74 Charger, it smelled for almost a year before it normalized. It was the paint, new gaskets and coating on exhaust manifolds that was causing the smell.
 
R

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,610
Reaction score
9,152
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Here ya go.
 

Attachments

  • Screenshot_2024-11-13_135315.jpg
    Screenshot_2024-11-13_135315.jpg
    95.6 KB · Views: 18
Grit dog

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
7,107
Reaction score
12,521
Location
Auburn, Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
Was gonnna say, if it’s exhaust smell in cab, fix that.
Cats will help but the CO will still be there if you have exhaust leaks.
 
You must log in or register to reply here.

Similar threads

T
454 getting pulled from suburban.. new cam?
Replies
14
Views
2K
Albrigap
Albrigap
T
85 suburban 454 exhaust setup
Replies
8
Views
952
TotalyHucked
TotalyHucked
T
454 build, which pistons to get to 9:1?
2
Replies
15
Views
2K
txaggie
T
T
3/4 454 suburban exhaust, modify factory or strip to new!
Replies
6
Views
943
Confused
Confused
Slooptin
454 exhaust recommendations
Replies
1
Views
1K
Craig 85
Craig 85

Latest posts

Forum statistics

Threads
44,425
Posts
957,613
Members
36,779
Latest member
The Dirty Burb
Top