Removal of Air Silencer:
This costs nothing and can be done by yourself. The only side affect is a slightly noticeable
burble sound when accelerating. If you have read our Year by Year pages, the addition of the
air silencer in 1987 reduced power by 2 to 3 BHP. By removing the air silencer, you will
gain that back but do not expect an improvement in acceleration. If this is your only
modification, do not waste your time. To remove the air silencer, which is located in the
front passenger fender, first remove the air filter. Next, remove the two bolts attaching the
air-box to the chassis. Once the air-box is removed, you will see three nuts that attach the
silencer. It is a little difficult to remove the silencer from the fender. (You will have
to try several different angles before freeing the silencer. It will probably help if you remove the screw retaining the fender lining to the fender at the front edge.)
180 Degree Thermostat:
A mistake some people make is to
replace the stock 195 degree thermostat with a much cooler 160 degree thermostat. This should
ONLY be done when an aftermarket chip is used and the manufacturer of that chip specifically
suggests the use of a cooler thermostat. In the case of stock engines using a thermostat
colder than 180 degrees, the computer will determine that the engine has not warmed-up yet and
will, therefore, make the Air-Fuel mixture richer. Secondly, cast iron wears more at colder
temperatures.
The best solution is to leave the 195 thermostat in and just get a heavy duty fan clutch and
a good aluminum radiator.
Under-Drive Pulleys:
These pulleys do not make more horsepower, they "free" horsepower. By adding a set of these
pulleys, the load on the engine by the accessories is reduced and, therefore, allows for
slightly more horsepower to be directed to the rear wheels.
Gears:
If you want to feel an increase in acceleration, get some gears. Again, these do not make
more BHP, they just improve acceleration by getting the 5.0L to its peak power output RPM
sooner. A stock '87 to '93 Mustang came with 2.73 gears while some were optionaed 3.08
and 3.27 gears. For the street, the 3.27s are a nice step up from the 2.73s. However, if
you visit the high end of your tach often, go with the 3.55s or 3.73s. These are a popular
modification with late model mustangs.