Factory Five Racing Type 65 Coupe, Assembly Manual

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www.factoryfive.com 508-291-3443
train. Remember that a 2,100 lb. car stresses the parts less than a 3,100 lb. Mustang does, so all
of the components will last longer and can take more abuse than they did on the Mustang. Check
out
www.factoryfive.com to see what we offer.
Gears
The Mustang 5.0 manual transmission car comes with either 2.73 or 3.08 rear end gear ratios from the
factory. If you can get a rear from an automatic car it will have 3.27 gears. There is an ID tag on the
rear differential. If you find that your rear end is missing its ID tag, there is a good chance that the rear
end was modified. To find out what ratio is on the differential, mark the pinion and axle at a start point.
Turn the axle exactly one rotation and count the number of rotations that the pinion makes compared to
the reference mark. For example: 3 ½ turns is a 3.55 rear ratio, etc.… The other way to check the ratio
out is to open the rear differential up and look on the ring gear. While the rear is open change the fluid.
This never gets done enough on the car.
Changing the gear ratio is one of the least expensive ways to improve your car’s performance and it is
easiest to do before assembly, since the rear is out of the car. If you know you are going to change the
gears get the 2.73 rear since these are the most readily available, the least expensive and the least
abused. All of the gear ratios work well with our car but we’ve found that installing an aftermarket 3.55
ratio really wakes the engine up. If you change the rear end gears, don’t forget to change the
speedometer sending unit gear so that the speedometer reads correctly unless you are running an electric
Speedometer, you can calibrate it. Wherever you get the rear gears from should be able to get the
correct gear for your application. If you cannot find the correct gear call “Texas Mustang Parts” 800-
527-1588,
www.texasmustang.com , they have the “hard to find” gears.
EFI Engines

There are three things an engine needs; air, fuel and spark. If you allow more of each of these
into the engine, it will make more power.