Zip Corvette: Offset and Backspacing (Link in Body)

During my research on new wheel/tire packages for my 76 Corvette, I came across some good info regarding offset and backspacing.

Zip Corvette

“Wheel back Spacing is very simple and is often confused with the offset. To determine a wheel’s offset you must first find the wheels back space. The back space can be measured in inches but should be converted to millimeters before proceeding to find the offset. To find the back space place a straight edge across the rear of the wheel and measure to the mount pad. The distance equals the wheels back space, which in this case is 6.75″. Multiply the back space by 25.4 to convert the back space to mm (6.75″ x 25.4mm = 171mm).

Wheel offset is the distance between the centerline of the wheel to the wheel mount pad. It is measured in millimeters and the outcome can result in a zero, positive or negative measurement. To have a zero offset, the wheel mount pad must be even with the centerline of the wheel. A positive offset means that the mount pad is shifted past the centerline towards the face of the wheel, while a negative offset means the mount pad is shifted past the centerline towards the rear, or the brake side of the wheel. To determine the offset of a wheel you must first measure the overall width of the wheel. Lets say the wheel measurements are 18″ x 9.5″. Now convert the width to millimeters by multiplying the width by 25.4mm (9.5″ x 25.4mm = 241mm). Next divide the wheel width by 2 to determine the wheels centerline (241mm/2 = 121mm). With the centerline and back spacing of the wheel determined and converted to millimeters simply subtract the centerline from the back spacing for the offset (171mm – 121mm = +50mm).”

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COPO Camaro

Before the marketing department created a COPO model it was the “Central Office Purchase Order” by which a few dealerships, notably Yenko and Gibb, ordered options not normally available for the Camaro. The Camaro of the 60s could not exceed a 400ci engine unless the COPO loophole was exploited.

Anyone that tells you that no COPO Camaro ever had a VIN nor were they street legal doesn’t know the history.

“Unlike the model built in 1969, the later versions of the COPO are not street legal.”

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LS3 Conversion (76 Corvette)

Anything, used, more than $3500, it’s time to go new.

Leaning toward the Hot Cam LS3 built engine. 480HP, 473lb.-ft.
Chevrolet Performance LS376/480 495HP Hot Cammed LS3

Powerplants I will consider, depending on price:
LS1 Aluminum 346ci 5.7L 1998-2002 Camaro, 305-315hp 1997-2004 Corvette, 2004-2005 GTO 345-350hp
LS2 Aluminum 368ci 6.0L 2005-2007 Corvette/ 2005-2006 GTO 400hp
LS3 Aluminum 381ci 6.2L 2008-2009 Corvette 435hp
LS6 Aluminum 346ci 5.7L 2001-2004 Z06 Corvette 405hp
L92 Aluminum 381ci 6.2L 2008-2009 Silverado Maxx, Denali, Escalade 403hp. This engine shares the same block as the LS3.

A brief summary of some differences.
Had differnet casting heads which had perimeter bolts and valve covers.
Ignition coils were mounted to the valve covers one at a time.
1998-1999 LS1 cars had a smaller throttle body cam, which caused the throttle to open to WOT faster than 2000+ cars
1998 cars had 28 lb fuel injectors from the factory
1998-2000 cars had a larger cam than the 01-02 cars
1998-1999 cars had more restrictive exhaust manifolds
1998-2000 cars had an LS1 intake with EGR
1998 only LS1 blocks had a much smaller cylinder sleeve that only tolerated a .005″ hone
1998 only cars had a different PCV system with the PCV valve located above the passenger side valve cover
1998 most cars did not have an idle adjustment screw on the throttle body. Some 98 cars do have the idle throttle stop set screws.
1998 cars have a completely different PCM from 99+ cars
A production shortage of F-body cams caused the use of a C5 cam to be installed in F-body LS1s for a very short time

1999-2000 cars switched to 26 lb fuel injectors
Cylinder heads and valve covers redesigned to have center bolts instead of perimeter bolts. Other than that, the heads were the same.
Redesigned cylinder sleeves that allowed for a small bore, up from .005″ in 1998 models.
1999 cars continued the LS1 intake with EGR provisions
1999 cars continued more restrictive exhaust manifolds and larger cam
1999-02 cars had a different PCV system with the valve located to the side of the intake manifold

Redesigned exhaust manifolds for new emissions standard actually flowed better and created a little more HP.
2000 continued use of LS1 Intake, EGR, smaller cam, and 26 lb fuel injectors
Throttle body cam was increased in size to slow the speed at which the car reaches WOT
Starting 2000 intake lids contained a seperate breather filter

A small percentage of 2001 and 2002 LS1s actually had LS6 blocks which had a different part number and a darker metal cast
Starting 2001, all LS1s came with an LS6 intake manifold without an EGR system
Advertised HP output was changed from 305 to 310 on base LS1s and from 320 to 325 on WS6s and SSs
2001-02 cars have a smaller cam from the Vortec truck engines to increase low end torque
2001-02 cars had 28 lb fuel injectors like the 98 cars (albeit different part numbers)

2002 – Last year of the F-body
2002 LS1 head gaskets redesigned. The new ones are a pressed metal, as opposed to the graphite ones and are no longer specific to the side of the car theyre installed on
2002 cars continued with the LS6 intake, 28 lb fuel inectors and smaller truck cam
2002 continued the use of an LS6 block in some LS1 F-bodies
A factory supported optional 345 HP option could be ordered from SLP

ST10 and LSx:


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2016 RAM 1500 Buildsheet

Equipment Listing
VIN 1C6RR7GT1GS279700
Vehicle Description 2016 RAM 1500 SLT 4X4

Monotone Paint
730 Amp Maintenance Free Battery
Electronic Stability Control
Anti-Lock 4-Wheel Disc Brakes
Prem Vinyl Door Trim w/Map Pocket
Front Height Adjust Shoulder Belts
Supplemental Side Air Bags
Advanced Multistage Front Air Bags
Supplemental Frt Seat Side Air Bags
Carpet Floor Covering
Front & Rear Floor Mats
Driver/Passenger Assist Handles
Rear Underseat Compartment Storage
Overhead Console
215MM Front Axle
3.21 Rear Axle Ratio
Conventional Differential Frt Axle
Conventional Differential Rear Axle
Tinted Glass Windows
Tinted Windshield Glass
Rear Power Sliding Window
Passenger Side Sun Visor w/Mirror

Rear View Mirror w/Microphone
Power Heated Mirrors, Fold-Away
Remote Keyless Entry with All-Secure
Sentry Key Theft Deterrent System
Air Conditioning
Dash Liner Insulation
Floor Tunnel Insulation
Instrument Cluster w/Display Screen
Instr. Panel Color Keyed Bezel
120 MPH Primary Speedometer
Temperature & Compass Gauge
Var Intermittent Windshield Wipers
Dual Note Electric Horns
12V Auxiliary Power Outlet
Power Accessory Delay
Power Locks
Pwr Front Windows, 1-Touch,Up & Down
Front Passenger Seat Belt Alert
Vehicle Information Center
Incandescent Tail Lamps
Rear Dome Lamp
Traveler/Mini Trip Computer
Halogen Quad Headlamps
Automatic Headlamps
Cargo and CHMSL Lamp
Bright Rear Bumper
Body Color Upper Fascia
Bright Front Bumper
Front License Plate Bracket
Front Wheel Spats
Ram’s Head Badge
Rear Wheel Well Liners
Body Color/Chrome Door Handles
B-Pillar Black out
Rear Wheel Spats
Ram 1500 Badge
4X4 Badge
Front Bumper Sight Shields
26 Gallon Fuel Tank
Speed Control
Maximum Steel Met. Clear Coat
Uconnect 5.0
6 Speakers
Power Rack and Pinion Steering
Front Heavy Duty Shock Absorbers
Rear Heavy Duty Shock Absorbers
Front Stabilizer Bar
Rear Stabilizer Bar
Tilt Steering Column
Tire Carrier Winch
17″ Steel Spare Wheel
Non Adjustable Pedals
Pickup Box
R1234YF A/C Refrigerant
7 Pin Wiring Harness
Trailer Tow w/4-Pin Connector Wiring
Locking Tailgate
Body Color Fuel Filler Door
English/USA Language
Seat Parts Module
Instrument Panel Parts Module
Door Parts Module
Front End Parts Module
Tire & Wheel Parts Module
Build To U.S. Mkt. Specifications
U.S. Long Term Daily Rental
Zone 42-Detroit
DS/6322 Vehicle Family
Four Wheel Drive (4WD)/(4X4)
2016 Vehicle Specifications
Price Class H – SLT
6 FT. Cargo Box
Quad Cab
1500 Series
Vehicle Order Tracking
U.S. Specifications Label
Nebraska Ship to State Code
Indiana Sold to State Code
Cloth 40/20/40 Prem Bench Seat
Black/Diesel Gray
Big Horn Regional Package
180 Amp Alternator
40/20/40 Split Bench Seat
Front Armrest w/Three Cupholders
Supp. Side Curtain Frt/Rr Air Bags

Rear 60/40 Split Folding Seat
Front Center Seat Cushion Storage
Folding Flat Load Floor Storage
Rotary Shifter-Black
All Automatic Transmissions
8-Spd Auto 8HP70 Trans (Buy)
Elec Shift On Demand Transfer Case
5.7L V8 HEMI MDS VVT Engine
All Vehicles W/Power Mirrors
115V Auxiliary Power Outlet
GPS Antenna Input
Power Lumbar Adjust
Power 10-Way Driver Seat
Black Exterior Mirrors
Fog Lamps
Active Grille Shutters
Bright/Bright Billets Grille
Hemi Badge
Big Horn Badge
50 State Emissions
Dual Rear Exhaust w/Bright Tips
Heavy Duty Transmission Oil Cooler
Exterior Mirrors w/Heating Element
Electronically Controlled Throttle
Heavy Duty Engine Cooling
Next Generation Engine Controller
Maximum Steel Met. Clear Coat
All Radio Equipped Vehicles
Fixed Long Mast Antenna
Steering Wheel Mounted Audio Ctrls
5.0″ Touchscreen Display
SiriusXM Satellite Radio
Audio Jack Input for Mobile Devices
Remote USB Port
Remote USB Port – Charge Only
Media Hub (USB, Aux)
All VP2 Radios
Leather Wrapped Steering Wheel
Full Size Temporary Use Spare Tire
P275/60R20 BSW All Season Tires
Goodyear Brand Tires
20X8.0 Aluminum Chrome Clad Wheels
All Aluminum Wheels
Center Hub
Tip Start
Class IV Receiver Hitch
Tire Pressure Monitoring Display
Locking Lug Nuts
Integrated Voice Command w/Bluetooth
Basic Owner’s Manual
Electronic Shift
Raised Ride Height
1-Yr. SiriusXM Radio Service
For More Info, Call 800-643-2112
Manuf Statement of Origin
5 Additional Gallons of Gas
Spring – Left Rear
Spring – Left Front
Spring – Right Rear
Spring – Right Front
GVW Rating – 6900#
Customer Preferred Package 2TZ
Customer Preferred Package 27Z
Price Protection – Code H
Long Term Daily Rental
Fleet Tracking Code
Group Discount
Prepaid Holdback
Sold Vehicle
Fleet Daily Rental W/Client Code
Fleet Option Editor
Fleet Sales Order
Special Scheduling Condition VI
Advance Payment Of SFPAP
4X4 Tracking
Enterprise Rent-A-Car
Warren Truck Assembly Plant
United States Region Group
NAFTA Region

Hits: 14

1994 Wrangler New Brakes

Ordered brake stuff for the Wrangler. Below is the info on the rear axle so I don’t forget (again).

VIN: 1FMYU24E0XUB76957
Car manufacture date: 1999
Mark of the vehicle: Ford
Auto model: Explorer
Vehicle motor: 4.0L V6 SOHC 16V
Trim of car: Sport 4WD
Number of identification: B76957
Shift type: 5-Speed Automatic | 5-Speed Manual

Hits: 15

Strobe (Wig Wag) Brake Lights in Iowa

NOTE: This information is dated 12/09/2014 and may become obsolete in the future

I’ve been researching the legality of strobe brake lights (sometimes referred to as wig-wags). I contacted the Polk County Sheriff Department to ask and they provided the Iowa Code below. I have highlighted the section of interest. It’s ambiguous at best, but it looks like they are legal by the “letter of the law”. I’ve contacted an attorney but have not heard back. Emphasis mine.

Of particular note is the “prohibited except” and the “intent to stop” language.

1. Definitions. As used in this section, unless the context
otherwise requires:
a. “Emergency medical care provider” means as defined in
section 147A.1.
b. “Fire department” means a paid or volunteer fire
protection service provided by a benefited fire district under
chapter 357B or by a county, municipality or township, or a private
corporate organization that has a valid contract to provide fire
protection service for a benefited fire district, county,
municipality, township or governmental agency.
c. “Member” means a person who is a member in good standing
of a fire department or a person who is an emergency medical care
provider employed by an ambulance, rescue, or first response service.

2. Prohibited lights. A flashing light on or in a motor
vehicle is prohibited except as follows:

a. On an authorized emergency vehicle.
b. On a vehicle as a means of indicating a right or left
turn, a mechanical failure, or an emergency stop or intent to stop.

c. On a motor vehicle used by a rural mail carrier when
stopping or stopped on or near a highway in the process of delivering
mail, if such a light is any shade of color between white and amber
and if it is mounted as a dome light on the roof of the vehicle.
d. On a vehicle being operated under an excess size permit
issued under chapter 321E.
e. A flashing blue light on a vehicle upon which a blue light
is permitted pursuant to subsection 3 of this section.
f. A flashing white light is permitted on a vehicle pursuant
to subsection 7.

g. Flashing red and amber warning lights on a school bus as
described in section 321.372, and a white flashing strobe light
mounted on a school bus as permitted under section 321.373,
subsection 7.
h. A flashing amber light is permitted on a towing or
recovery vehicle, a utility maintenance vehicle, a municipal
maintenance vehicle, a highway maintenance vehicle, or a vehicle
operated in accordance with subsection 6 or section 321.398 or
i. Modulating headlamps in conformance with 49 C.F.R. §
571.108 S7.9.4. are permitted on a motorcycle.
j. On a vehicle being operated as an escort vehicle for a
funeral procession as provided in section 321.324A.
3. Blue light. A blue light shall not be used on any vehicle
except for the following:
a. A vehicle owned or exclusively operated by a fire
b. A vehicle authorized by the chief of the fire department
if the vehicle is owned by a member of the fire department, the
request for authorization is made by the member on forms provided by
the department, and necessity for authorization is demonstrated in
the request.
c. An authorized emergency vehicle, other than a vehicle
described in paragraph “a” or “b”, if the blue light is
positioned on the passenger side of the vehicle and is used in
conjunction with a red light positioned on the driver side of the
A person shall not use only a blue light on a vehicle unless the
vehicle meets the requirements of paragraph “a” or “b”.
4. Expiration of authority. The authorization shall expire
at midnight on the thirty-first day of December five years from the
year in which it was issued, or when the vehicle is no longer owned
by the member, or when the member has ceased to be an active member
of the fire department or of an ambulance, rescue, or first response
service, or when the member has used the blue or white light beyond
the scope of its authorized use. A person issued an authorization
under subsection 3, paragraph “b”, shall return the authorization
to the fire chief upon expiration or upon a determination by the fire
chief or the department that the authorization should be revoked.
5. When used. The certificate of authorization shall be
carried at all times with the certificate of registration of the
authorized vehicle and the operator of the vehicle shall not
illuminate the blue or white light except in any of the following
a. When the member is en route to the scene of a fire or is
responding to an emergency in the line of duty requiring the services
of the member.
b. When the authorized vehicle is transporting a person
requiring emergency care.
c. When the authorized vehicle is at the scene of an
d. The use of the blue or white light in or on a private
motor vehicle shall be for identification purposes only.
6. Amber flashing light. A farm tractor, farm tractor with
towed equipment, self-propelled implement of husbandry, road
construction or maintenance vehicle, road grader, or other vehicle
principally designed for use off the highway which, when operated on
a primary or secondary road, is operated at a speed of thirty-five
miles an hour or less, shall be equipped with and display an amber
flashing light visible from the rear at any time from sunset to
sunrise. If the amber flashing light is obstructed by the towed
equipment, the towed equipment shall also be equipped with and
display an amber flashing light as required under this subsection.
All vehicles specified in this subsection which are manufactured for
sale or sold in this state shall be equipped with an amber flashing
light in accordance with the standards of the American society of
agricultural engineers.
7. Flashing white light. Except as provided in section
321.373, subsection 7, and subsection 2, paragraphs “c” and
“i” of this section, a flashing white light shall only be used on
a vehicle in the following circumstances:
a. On a vehicle owned or exclusively operated by an
ambulance, rescue, or first response service.
b. On a vehicle authorized by the director of public health
when all of the following apply:
(1) The vehicle is owned by a member of an ambulance, rescue, or
first response service.
(2) The request for authorization is made by the member on forms
provided by the Iowa department of public health.
(3) Necessity for authorization is demonstrated in the request.
(4) The head of an ambulance, rescue, or first response service
certifies that the member is in good standing and recommends that the
authorization be granted.
c. On an authorized emergency vehicle.
The Iowa department of public health shall adopt rules to
establish issuance standards, including allowing local emergency
medical service providers to issue certificates of authorization, and
shall adopt rules to establish certificate of authorization
revocation procedures.

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