What could this random tube attached to the exhaust be?

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.

Chris64

Chris64

Member
Joined
Sep 16, 2024
Posts
44
Reaction score
75
Location
San Diego
First Name
Chris
Truck Year
1974
Truck Model
K20
Engine Size
350
Surely someone can explain this mystery tube to me. It's hose clamped to the exhaust for some reason. It's not drilled out or anything if you look down the tube. It's just clamped to it and barely hanging on. Chesterton's-random-exhaust-tube. It's better to figure out why it's there before removing :)

Excuse the rust. I'm working on it.
You must be registered for see images attach
 
Redfish

Redfish

Full Access Member
Joined
Nov 6, 2021
Posts
2,600
Reaction score
14,030
Location
Prairieville, LA
First Name
Andrew
Truck Year
1987
Truck Model
V1500
Engine Size
350/5.7
It almost looks like a poorly fabricated heat riser. The truck originally had a heat riser that ran from the exhaust manifold straight up to the neck of the air intake duct of the air cleaner. Maybe the Previous Owner was trying to recreate that?
 
Grit dog

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
6,877
Reaction score
12,023
Location
Auburn, Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
99% sure someone fabbed up a connection for a carburetor heat riser for an OE air cleaner like was present on original OE exhaust manifolds.
 
Chris64

Chris64

Member
Joined
Sep 16, 2024
Posts
44
Reaction score
75
Location
San Diego
First Name
Chris
Truck Year
1974
Truck Model
K20
Engine Size
350
Redfish said:
It almost looks like a poorly fabricated heat riser. The truck originally had a heat riser that ran from the exhaust manifold straight up to the neck of the air intake duct of the air cleaner. Maybe the Previous Owner was trying to recreate that?
Click to expand...
What function did this serve? Should I complete this?
 
Radiohead

Radiohead

That guy on the Columbia
Joined
Mar 17, 2022
Posts
2,457
Reaction score
8,016
Location
Low Earth Orbit where it's safer
First Name
Eric
Truck Year
MCMLXXIX
Truck Model
C-20 Silverado Camper Special
Engine Size
454 crazy cubes, or 7.4 luscious litres
On the stock air cleaner housing there is a diverter valve that has some of that metallic flex tubing attached that goes onto that piece of pipe. When it's cold, vacuum is applied to position that valve, allowing heated air to go into the carb and when operating temp is reached, that valve will retract to allow "cold" air to the carb.

I could have the vacuum application backwards, but that's how it works and why.

Being in San Diego, you may never need it, but go anywhere cooler, it will help the cold driveability. I'd put it back to operational.
 
R

RaisedK5

Full Access Member
Joined
Sep 12, 2021
Posts
113
Reaction score
238
Location
Memramcook, New Brunswick, Canada
First Name
Leland
Truck Year
1975
Truck Model
Blazer
Engine Size
350
Similar to this.

Hedman Performance Group

Hedman Hedders & Trans-Dapt Performance Products are two of the hot rod industries original manufacturers, dating way back to 1954. Known primarily for exhaust headers, engine mounts, carburetor spacers and adapters, and chrome and aluminum customizing accessories, these two pioneering companies...
www.hedman.com www.hedman.com
 
77Matt

77Matt

Member
Joined
Mar 21, 2024
Posts
49
Reaction score
26
Location
TO, CA
First Name
Matt
Truck Year
1977
Truck Model
C15
Engine Size
5.7L 350 V8
Does exhaust actually come out of that pipe? The heat rise isn’t actually connected to the exhaust but sits up against it so hot air rises.
 
emoze

emoze

Member
Joined
Sep 28, 2020
Posts
33
Reaction score
14
Location
near Sacramento
First Name
lary
Truck Year
1984
Truck Model
C20
Engine Size
454
in CA, pre-76 is exempt from smog inspections; just remove it & enjoy the truck ... (unfortunately my 84 is not exempt)
 
H

hdchevy

Junior Member
Joined
Sep 9, 2024
Posts
6
Reaction score
6
Location
Florida
First Name
HD
Truck Year
1973
Truck Model
K10
Engine Size
350
77Matt said:
Does exhaust actually come out of that pipe? The heat rise isn’t actually connected to the exhaust but sits up against it so hot air rises.
Click to expand...
It is designed to channel hot air from the exhaust manifold to a value in the factory air cleaner. No exhaust just hot air.
 
59840Surfer

59840Surfer

Full Access Member
Joined
Oct 8, 2020
Posts
206
Reaction score
335
Location
Montana
First Name
Joe
Truck Year
1986
Truck Model
K5
Engine Size
350 Stroker to 383 with a 400 crank, Crane Cam, Q-Jet, single 3.5" exhaust..
Kinda like the old VW Bug heaters that took heat from around the exhaust manifolds and routed it into the cabin. Nobody died of whom I am aware of this system although it seems kinda iffy.

I liked the Corvairs better --- the early ones had actual gasoline-fired furnaces in the front cargo space that could heat you to incendiary values without the engine running. I melted the soles off my Uggs once in my 1963 Corvair --- BT- DT.
 
R

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,304
Reaction score
8,441
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
59840Surfer said:
Kinda like the old VW Bug heaters that took heat from around the exhaust manifolds and routed it into the cabin. Nobody died of whom I am aware of this system although it seems kinda iffy.

I liked the Corvairs better --- the early ones had actual gasoline-fired furnaces in the front cargo space that could heat you to incendiary values without the engine running. I melted the soles off my Uggs once in my 1963 Corvair --- BT- DT
Click to expand...
The early bugs were the fun ones,before they went fresh air,.( that's the system that blew air through skins around the exhaust manifolds) the previous ones blew the air that cooled the engine into the car,oil leaks,head gasket leaks,and all.
 
You must log in or register to reply here.

Similar threads

C10_Blackie
Recognize this?
2
Replies
17
Views
2K
JBswth
J
S
Engine / exhaust noise care to take a stab at what it might be?
Replies
4
Views
406
SirRobyn0
S
hey mister
Dead in the water.
Replies
1
Views
277
Catbox
Catbox
A
Help me figure out what to do with this truck
Replies
11
Views
2K
PhotonFanatic
PhotonFanatic
Bullet Bob
No brakes and unable to get one side to bleed
Replies
4
Views
963
Bullet Bob
Bullet Bob

Latest posts

Forum statistics

Threads
43,941
Posts
946,163
Members
35,986
Latest member
CapAhab
Top