This page is devoted to illustrating little-known facts and exposing fallacies about 428 Cobra Jet Mustang production. So much information has been lost or mis-represented over the years, so I thought it important to capture significant details as they come to light. Can you guess which are fact, and which are fallacy?
Special thanks to Kevin Marti, who helped clarify some of the issues below. Please feel free to submit additional information for inclusion on this page.
Use the links next to each statement to scroll to the answers automatically.
True or False: Ford did not produce any 1970 428 Cobra Jet Mustangs with a 4-speed transmission and air conditioning.
True or False: All 428 Cobra Jet Mustangs were equipped with single-point distributors.
True or False: All 428 Cobra Jet Mustangs were equipped with automatic choke carburetors.
True or False: Factory 1968 428 Cobra Jet Mustang drag racing vehicles can be identified by their VIN.
True or False: Super Cobra Jet blocks have higher nickel content than Cobra Jet blocks.
True or False: 428 Super Cobra Jets were only available in 1969 and 1970.
True or False: Ford produced 1968 Mustangs with 428 Police Interceptor Q-code engines.
True or False: Some 1969 428 Cobra Jet Mustangs were equipped with 1968-style ram air systems.
True or False: 428 Super Cobra Jets were available both with and without ram air induction.
True or False: 428 Cobra Jet and Super Cobra Jet heads are identical.
True or False: 428 Cobra Jets were not equipped with a rev limiter.
True or False: All 428 Super Cobra Jets came equipped with "snake" valve covers.
True or False: Ford never stamped partial VIN numbers on 428 Cobra Jet blocks.
True or False: All 428 SCJ Mustangs equipped with "V" code 3.91:1 rear end gears came with a Ford "Traction-Lok" differential.
True or False: All 428 SCJ Mustangs equipped with "W" code 4.30:1 rear end gears came with a DAPCO "Detroit Locker" differential.
True or False: 428 SCJ engines were originally equipped with forged pistons.
1. Ford did not produce
any 1970 428 Cobra Jet Mustangs with a 4-speed transmission and
air conditioning.
False! According to Ford production records
researched by Kevin Marti, Ford produced eleven 1970 Mach 1
Mustangs with a 428 CJ engine, 4-speed transmission, and air
conditioning. All were produced fairly late in the model year,
with eight produced at Dearborn, one produced at San Jose, and
two produced at Metuchen. Five of the cars were Q codes, and six
were R codes. All were equipped with 3.25:1 rear gears; two were
limited slip (code "R") and nine were open (code
"9"), and only one was equipped with a factory
tachometer. All eleven of the VINs are known to the registry, but
the location and condition of some of these cars is still a
mystery. There are many written reports that describe how air
conditioning couldn't be ordered with a 428 CJ and 4-speed
transmission in 1970, but towards the end of the model year Ford
definitely let a few slip through.
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2. All 428 Cobra Jet
Mustangs were equipped with single-point distributors.
False! While it's true that most
428 CJ distributors used a single set of points, the distributor
used for 1970 4-speed applications was a dual point, dual vacuum
advance distributor. This distributor can be identified by
casting number D0ZF-12127-C.
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3. All 428 Cobra Jet
Mustangs were equipped with automatic choke carburetors.
False! While it's true that most 428 CJ
carburetors used an automatic choke, the 1970 carburetors used a
manual, cable-activated choke. These carbs can be identified by
casting numbers D0ZF-9510-AA (4-speed without air conditioning),
D0ZF-9510-AB (automatic without air conditioning), D0ZF-9510-AC
(4-speed with air conditioning), and D0ZF-9510-AD (automatic with
air conditioning).
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4. Factory 1968 428 Cobra
Jet Mustang drag racing vehicles can be identified by their VIN.
True! In late December 1967 (date code
30M), Ford produced 50 Wimbledon White sportsroof Mustangs with
black vinyl interiors for drag racing duty. The vehicles were
numbered sequentially, starting with VIN 8F02R135007 and ending
with VIN 8F02R135056.
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5. Super Cobra Jet blocks
have higher nickel content than Cobra Jet blocks.
False! Finding the word "Super"
stamped on some Cobra Jet blocks has led some people to believe
that the block is a high nodular iron casting or is somehow
otherwise stronger than other 428 Cobra Jet blocks. According to
several sources all 428 Cobra Jet, 428 Super Cobra Jet, and 428
Police Interceptor engines were assembled on the same production
line and this stamping helped identify engines whose bottom ends
required Super Cobra Jet components.
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6. 428 Super Cobra Jets
were only available in 1969 and 1970.
True! The 428 Super Cobra Jet engine was
first available in 1969, exclusively available when ordering
either of the optional 3.91:1 or 4.30:1 rear end gear ratios. The
Super Cobra Jet included a number of reciprocating assembly
changes to stand up to the rigors of drag racing, including beefy
capscrew connecting rods, cast pistons, and a crankshaft,
flywheel or flexplate, and harmonic balancer distinct from the
standard 428 Cobra Jet. An external engine oil cooler mounted in
place of the driver's side horn (the horn gets relocated to the
passenger side) and the distinct balancer with counterweight are
the only visible clues to what lies within.
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7. Ford produced 1968
Mustangs with 428 Police Interceptor Q-code engines.
False! Kevin Marti confirms that the
records his company has licensed from Ford do not include any
1968 Mustangs equipped with a "Q" engine code. The VINs
I've seen for alleged Q-code cars have all turned out to be cars
that originally left the factory as C-code (289-2v) cars, meaning
someone modified the cars and altered the VIN -- and that's not
legal.
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8. Some 1969 428 Cobra
Jet Mustangs were equipped with 1968-style ram air systems.
False (probably)! According to some
sources, some of the very first 1969 ram air Cobra Jet Mustangs
were not equipped with the familiar "shaker" hood
scoop. Instead, they were fitted with the 1968-style flapper and
fixed hood scoop. I've never been able to confirm this
information, though. If anyone has any factual information it
would be most appreciated!
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9. 428 Super Cobra Jets
were available both with and without ram air induction.
True! 428 Super Cobra Jets were available
both with ram air induction (identified with VIN engine code
"R") and with a standard air cleaner assembly
(identified with VIN engine code "Q"). The engine code
isn't what determines installation of a Super Cobra Jet engine;
it's the rear end codes of "V" (3.91:1 Ford
traction-lok) or "W" (4.30:1 traction-lok or Detroit
Locker) that make the difference.
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10. 428 Cobra Jet and
Super Cobra Jet heads are identical.
True! 428 Cobra Jets and Super Cobra Jets
used the exact same induction systems and cylinder heads. What
makes a 428 Super Cobra Jet unique is the specialized
reciprocating assembly.
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11. 428 Cobra Jets were
not equipped with a rev limiter.
False! In 1970, Ford added an electronic
engine RPM limiter/governor to Mustangs equipped with 428 Cobra
Jet engines and 4-speed transmissions. These units limited spin
up to 5,800 rpm in an attempt to keep warranty claims to a more
manageable level. Fortunately (or unfortunately, depending on how
you look at it), removal was quite easy and a great many of these
units have failed to remain attached to the cars they were
originally installed in.
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12. All 428 Super Cobra
Jets came equipped with "snake" valve covers.
False! The popular "snake"
aluminum valve covers were not installed on all Super Cobra Jet
engines. Original valve covers installed in 1969 include chromed
steel, plain finned aluminum, and finned aluminum with cobra and
"428 Cobra Jet" castings. Both the plain finned
aluminum and finned aluminum with cobra and "428 Cobra
Jet" appeared in 1970. Plus, the "snake" covers
could be bought over the counter at any Ford dealership and
appear to have been a popular dress-up item of the period.
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13. Ford never
stamped partial VIN numbers on 428 Cobra Jet blocks.
False! Starting in 1968 Ford began stamping
partial VIN information on a pad just under the back of the
driver's side cylinder head of all factory-installed 428 Cobra
Jet engines to comply with Government-mandated regulations.
Service blocks didn't receive VIN stampings, so as engine swaps
have taken place over time it has become very difficult to keep
up with this "matching numbers" reality. Once an engine
is installed it's practically impossible to see this stamping
even if it does exist! Ford also stamped partial VINs on
transmission cases, so take a peek at when you next have a
chance.
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14. All 428 SCJ
Mustangs equipped with "V" code 3.91:1 rear end gears
came with a Ford "Traction-Lok" differential.
True! Starting in 1969 Ford began offering
an optional 3.91:1 gear ratio that used Ford's Traction-Lok
differential, which used a clutch pack for quiet, streetable rear
wheel locking under hard acceleration in a straight line. Order
this option and you also got a 428 SCJ engine!
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15. All 428 SCJ
Mustangs equipped with "W" code 4.30:1 rear end gears
came with a DAPCO "Detroit Locker" differential.
False (most likely)! Contrary to most
published literature, documentation describing the Detroit Locker
doesn't appear from Ford until approximately November 1969 --
well into the 1970 model year. Earlier documentation that I've
seen, such as original invoices, clearly describes the
"W" code differential as a "Traction-Lok"
differential. This is an ongoing research area, and it would be
very helpful if anyone who might have documentation describing an
original Detroit Locker installation in a 1969 Mustang could
share their insights. See the CJ vs. SCJ
page for details.
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16. 428 SCJ engines
were originally equipped with forged pistons.
False! Contrary to most published
literature, 428 SCJ engines were originally equipped with cast
pistons. Some of the confusion may be because of the later 429
Super Cobra Jet, which was originally equipped with forged
pistons. See the CJ vs. SCJ page for
details.
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© 1999 Scott A. Hollenbeck. All Rights Reserved.