FAQ

How do I get a copy of the Ford Performance parts catalog?
What size are the fuel injectors in my Mustang?
  • The 1986-95 HO 302 Mustangs use a 19-pound injector.
  • The 1996-2003 4.6 SOHC Mustangs use a 19-pound injector.
  • The 1993-95 Cobra Mustangs use a 24-pound injector.
  • The 1996-2001 Cobra Mustangs use a 24-pound injector.
  • The 2003 Cobra Mustangs use a 39-pound injector.

  • Note: See the FRPP catalog to determine if you need EV1 style or EV6 style injectors.
What is the crankshaft balance factor of my 302 or 351W/C engine?
  • 1968-80 302 engines were built with a 28-ounce imbalance factor.
  • 1981-2001 302 engines were built with a 50-ounce imbalance factor.
  • 1969-97 351W engines were built with a 28-ounce imbalance factor.
  • 1970-74 351C engines were built with a 28-ounce imbalance factor.

  • Note: Severe engine damage will result if you use the wrong flywheel or damper on your engine.
I have heard that an axle gearset change is a very effective way to increase performance in my Mustang. What gear ratio do you advise that I use?
  • 1986-95 Mustangs with a 5.0 and a 5-speed work well with 3.55 gears.
  • 1986-95 Mustangs with a 5.0 and an automatic work well with 3.73 gears.
  • 1996-2003 Mustangs with a 4.6 SOHC and a 5-speed work well with 3.73 gears.
  • 1996-2003 Mustangs with a 4.6 SOHC and automatic work well with 4.10 gears.
  • 1996-2001 Mustang Cobras with the 4.6 DOHC/5-speed work well with 3.73s.

  • 2005-2012 Mustang GT works well with 3.73s.

  • Note: The above suggestions are general recommendations. Gear-ratio selections may change depending on modifications to your engine.
I have changed the gears in my Mustang; how do I correct the speedometer?
  • Changing your axle gear ratio can throw off the calibration of your speedometer, so purchasing a different speedometer drive gear from your local Ford or Lincoln/Mercury dealer will be necessary for your speedometer to more accurately reflect actual readings. A speedometer gear usage chart is printed in the FRPP catalog that can guide you to the proper speedometer gear needed to correct your speedometer. 2005-12 Mustangs can correct the speedometer using the ProCal tool included in Ford Performance Power Upgrade Packs and Supercharger Kits.
Clutch/transmission installation tips for 1986 and newer V-8 Mustangs

  • The flywheel to crankshaft bolts must be hand-torqued to 75-85 ft./lbs. (302/351W) and 54-64 ft./lbs. (4.6L) The 10.5" pressure plate bolts must be torqued to 12-24 ft./lbs. and 11" pressure plate bolts to 33 ft./lbs. + 1/4 turn.

  • Be sure to use the alignment dowels in the flywheels. Pressure plate bolts and alignment dowels for the 10.5" clutch can be purchased using PN M-6397-A302. Pressure plate bolts N808969-S100 and alignment dowels D1FZ-6397-B are for the 11" pressure plate.

  • Evenly tighten bolts in a circular direction one turn at a time. Bellhousing alignment is crucial for proper clutch and transmission function.

  • Due to production tolerances of engine blocks and bellhousings, it is possible for the transmission centerline and crankshaft centerline to be misaligned. Misalignment can cause transmission gear wear, transmission jumping out of gear, driveline vibration, clutch pedal vibration, pilot bearing noise, release bearing noise or excessive clutch spin time. It may also damage the pilot bearing, transmission mainshaft bearing and clutch hub. It will also cause harsh shifting.

  • Before installing the bellhousing, check the block mounting surface and bellhousing surfaces for nicks, dents, paint debris, etc. These are some things that could affect the accuracy of your measurements.
How do I check bellhousing alignment?
  • The first step is to check bellhousing face runout. You are checking for parallelism of the back of the bellhousing to the back of the block. Install the dial indicator. Rotate the crankshaft and mark down the reading. Be sure to push the crankshaft against the thrust bearing for an accurate reading. Maximum runout is .010.

  • The next step is checking bellhousing bore runout. You are checking to see if the bellhousing bore centerline is aligned with crankshaft centerline. Reposition the dial indicator in the bellhousing bore. Rotate the crankshaft and mark down the readings. Maximum out of concentricity is .015. If the bore runout is out of spec. install appropriate offset dowels.