Stealth Conversions, The Parts Division of JTR (Jaguars That Run)

Header for Chevrolet Colorado 5-cylinder

No Longer Available — see NEW BOLT-IN HEADER, 5 CYLINDER

Stealth Conversions
The Parts Division of JTR (Jaguars That Run)

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Header for Chevrolet Colorado 5-cylinder
Header, Chevrolet Colorado 5-cylinder

STEALTH CONVERSIONS Header for Chevrolet Colorado 5-cylinder


#COL-401 – mild steel: $420.00, including UPS Ground

#COL-401C – ceramic coated: $520.00, including UPS Ground

Header, Chevrolet Colorado 5-cylinder

••• click the following link to See New BOLT-IN HEADERS

The JTR/Stealth Conversion’s long-tube header is designed to improve power and torque.

The primary tubes are 1-5/8" diameter. The lengths of the primary tubes are 29" to 34".

The collector is 3" diameter.

The performance improvements on an otherwise stock 2005 extended cab ZQ8 with the 5-cylinder/automatic and 3.42 gears are as follows:


0–60 mph, 7.7 seconds (average of three runs)

1/4 mile, 15.9 seconds at 89.2 mph (average of three runs)

Modified with JTR/Stealth ram-air intake:

0–60 mph, 7.5 seconds (average of three runs)

1/4 mile, 15.7 seconds at 90.4 mph (average of three runs)

Modified with JTR/Stealth ram-air intake and header:

0–60 mph, 7.2 seconds (average of three runs)

1/4 mile, 15.4 seconds at 91.6 mph (average of three runs)

All measurements were made with a Vericom 2000 accelerometer/performance computer.

All of the above tests were done with the outside air temperature at 45 to 50 degrees F, which helps explain why the 1/4 mile performance and 0-60 mph times are better than most other published information.

The outside air temperature has a very noticeable difference in the 1/4 mile performance — this is, in part, due to the high compression ratio of the stock engine. 

When the truck was tested in 70 degree weather, the quarter mile times were lower by about .4 seconds, the trap speeds were slower by about 2 mph, and the 0-60 times were about 0.5 seconds slower. This also provides proof of the performance benefits of a cold-air intake.

All tests were done with a full tank of 87 octane gasoline.

Using a formula to calculate horsepower based on 1/4 mile performance, the header adds about 10 hp. The header and ram-air combined adds about 20 hp.

This header will not fit on the 4wd trucks or the Hi-rider, Z71 trucks (trucks with torsion bar front suspension).

Installation requires modifying the heater hoses to provide clearance between the header and the heater hoses.

On trucks with automatic transmissions, the dipstick tube will need to be bent slightly, and the bracket that attaches the top of the dipstick tube to the cylinder head will have to be bent.

The exhaust system requires cutting and welding which can normally be done by most muffler shops.

The header is not smog legal, and is for racing and off-road use only.



The basic installation will probably take three to four hours -- this does not include the trip to the muffler shop.

A muffler shop should be able to connect the header to the exhaust in less than an hour.

Colorado, stock heater hoses

Stock Heater Hoses


Remove the stock exhaust manifold. This requires removing the air cleaner assembly, and the intake ducting going to the engine.

The heater hoses will have to be shortened by cutting a few inches from the upper sections that connect to the firewall fittings.

Colorado, heater hose modification


Disconnect the heater hoses from the firewall fittings by squeezing the plastic connectors and gently pulling the hoses from the firewall fittings. This should be done to avoid damaging the heater core when shortening the hoses.

Before disconnecting the hoses, drain about 1 quart from the cooling system.

Remove the heater hoses from the plastic fittings. Cut the hoses so that an inch of straight section can be used to connect the hoses back onto the plastic fittings.

Colorado, modified heater hoses

Heater Hoses, Modified


Re-install the heater hoses.

Colorado, header installation


The header is installed from the top of the engine compartment.  It is a tight fit, and requires some careful manuvering to get the collector between the engine and the frame rails.

Use the stock metal gasket between the header and the cylinder head.

Use the stock bolts.


Check for clearance between the frame and the header tubes.

The clearance between the fame and the header is very tight, and we have had complaints about the header touching the frame on some installations. If the header tube is too close to the frame (less than 1/2 "), mark the section of the header tube, remove from the truck, and use a small hammer to flatten the header tube as needed.


Install the transmission dipstick tube between the 3 and 4 header tubes. The bracket that bolts to the cylinder header will have to be bent.



Colorado, oxygen sensor and exhaust hook-up


The oxygen sensor is installed at the collector as shown.

The wires need to be extended about 2-1/2 feet.


Connecting the header to the exhaust normally requires a trip to a muffler shop. The header can be connected to the catalytic converter as shown by using a 3" to 2-1/2" reducer at the header, and having a muffler shop fabricate a  2-1/2" diameter headpipe to connect between the reducer and the catalytic converter.

For best sealing, use a copper gasket.

Colorado, stock heater hoses


If the truck is started without connecting the Oxygen sensor, the "Check Engine Light" will come on. The "Check Engine Light" will not turn off by disconnecting the battery.

To turn the "Check Engine Light" off, a scanner designed for OBD2 diagnostics is required.

The scanner plugs into the diagnostics port located under the dash, near the hood latch release lever.

Scanners, similar to the unit shown above can be purchased for less than $100 from most auto parts stores.


After first installing the header, your engine will probably surge during acceleration.

The engine computer needs to re-adjust itself due to the improved exhaust scavenging provided by the header. Normally, the engine computer will "learn" by itself using a term called "block learning." The surging will go away within a few hours of driving, but it can take several days for the computer to completely compensate for the header under all driving situations.

To make the computer learn faster, disconnect the battery for one minute. This will erase the previous "block learning." The engine will still surge for a short time, but it will normally go away within 1/2 hour of driving.

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JTR engine swapping manuals are available directly from JTR Publishing,
As well as through a number of retailers, including:
Summit Racing (S-10: Part #JTR-S10; Jaguar: Part #JTR-JAG),
JEGS (S-10: Part #116549; TPI & TBI: Part #117942),
Steve Smith Autosports (S-10: Part #S212; TPI & TBI: Part #S195), and
Classic Motorbooks (S-10: Part #116549; TPI & TBI: Part #117942;
  Jaguar: Part #118438; Datsun Z: Part #115501; Volvo 200: Part #122587).

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