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15 Posts
Discussion Starter · #1 ·
I recently purchased a 1992 Mustang Gt with 289, with a c4 tranny and shift kit, with a ****** z Gate shifter.... I wanted to know some things i could to with the 289 carbed motor.... Im pretty good with 302 fuel injected, but i know nothing about carbaretors.

4,809 Posts
What are the goals for the car?

15 Posts
Discussion Starter · #3 ·
well im wondering what kind of bolt on will help my car, I have a shift kit in my car but I also heard on the back of the c-4 tranny there is a bolt to turn inward to make it shift harder....Things I can do to my car for like 300 Dollars a pop

103 Posts
You'd be looking at the typical carb'd hop up scenario.

Heads, cam/timing set, intake, exhaust, ignition, carb.
You'd gain some from any one of them, but wouldn't
get the full benefit from any one untill you have them
all as the whole system has to match to get the best
out of the individual items.

Good news is you can do them 1 at a time, I don't
know that which first makes any big difference.
I'd also watch for used intakes and carb, as well
as headers/exhaust, you can save some $ there.
I even found a used Dynomax catback setup from
a guy that wrecked.

Anyway, from the top:

I'd look for GT40P iron heads off the later explorer 5.0's.
You can find them rebuilt with better springs, seals, and
SS valves pretty reasonable. Do a Google search, also
check ebay, I've seen them on there.
Look under Articles for a GT40P article, scroll down a ways.

For a fairly high perf street motor, hands down the best
intake is an Edelbrock Performer RPM. For a little milder
street motor that won't see much over 5000, the regular
Performer will match a milder cam etc better.

For a carb, I'd look for a vac secondary 600 Holley.
The stock jetting would even be pretty close, all you'd have
to tune is your power valve (hook a vacuum gauge
to the motor and see what your cruise vacuum and
part throttle normal acceleration mode vacuum is,
then put in a power valve that opens a couple inches
lower than those figures) and your vac secondary
spring so it doesn't open too soon and bog the motor
or open too late. Not hard to do.

For exhaust, I'd look for small diamater long tubes
which would give you the best low/mid range torque
and throttle response, or even a set of shorties,
equal length being the best there. Have to be P
specific headers if you have P heads. Add a decent
2-1/4" dual exhaust with X pipe and a set of
inexpensive turbo style mufflers.

For ignition, if you don't have electronic now, go to
a junkyard and capture a Ford Duraspark system.
It's electronic (CD) but not computer controlled.
It'll vastly improve your starting, idling, and running,
as well as mileage. The distributor can be curved
just like a regular points distributor. There are 2
different versions of the Duraspark, one being
better than the other. There should be info on
all that here, scroll
down in the tech section for an electronic distributor
article, or he's also got a forum linked on that site where
you can ask. Here's a diagram just in case
I'd recommend AC Rapidfire plugs, they've got
a star shaped center electrode and the tapered/side
style side electrode, and are reasonably priced.
Those features give you better power and mileage.
Then a decent set of aftermarket performance wires
and coil.

For cam, I'd look at Comp Cams or Lunati for a flat
tappet hydraulic cam/lifter kit. Look at their descriptions,
but for a mild street engine I'd go not over 215 degrees
at 050 on the intake and 460ish to not over 500 lift.
For a higher perf cam, I'd look at 215 to 220+ maybe
a little duration and not over low 500's lift. Don't forget
to check your piston to valve clearance! I used a set
of light tension checking springs, and checked clearance
while turning the motor over near where the intake valve
starts to open and the exhaust valve closes - the overlap
area. Ask the cam mfg for details. You have to take into
account the lifter preload. Most name brand aftermarket
roller timing setups are decent.

You can also do things like go to a Taurus 3.8 electric
fan which can free up as much as 15 hp on the highway,
as well as allowing the engine to warm up quicker, and
give you up to 2 mpg better. I used a soft start, variable
speed Flex A Lite controller that you don't need any
relays with. Summit has them, you need the bigger

Here's another forum that might have some help

That should turn a 289 into a surprisingly spirited motor,
and you could use all that stuff on a 302, too.

Just FYI
(an early Explorer intake is like a Cobra and can be had quite cheap)

THAT ought to keep you busy for awhile! :)

Good luck!
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