How to Install Flowmaster Force II Stainless Steel Cat-Back Exhaust - Single Side Exit on your F-150

1) Raise the vehicle up on a hoist or rack to working height. If you do not have access to a hoist or rack raise the vehicle and support securely with jack stands.

2) Begin by applying a lubricant to each of the rubber hanger mounts, as well as the clamp and flange bolts. This will make the removal and installation process much easier.

3) Remove the two bolts at the front flange connection, and loosen the band clamp connection that is behind it on the inlet pipe. There is locking pin at this joint, so to separate it you will have to slide the muffler assembly back a little bit, twist the front inlet pipe clockwise, and then you can slip the front inlet pipe back to remove.

4) Now you can slide the muffler tailpipe assembly to the rear to disengage the rubber hanger mounts that support it. Once free, the assembly can be removed by working it forward over the rear axle. (If you are working on the ground it may be easier to cut the tailpipe off at the rear of the muffler to simplify removal)

1) Before installing anything, prep the clamps supplied in the hardware kit by removing the nuts, and applying a thick lubricant such as white grease or anti-seize to the threads.

2) Based on production variations this is a list of cab designs, bed lengths and wheel bases that outlines the requirements for the front inlet pipe. Please follow the instructions for your particular wheelbase listed on the next page. Double check all measurements before cutting your inlet pipe:

126” WB - Regular Cab/6.5’ Bed - Trim 18” off the inlet pipe #26336S (do not use #26206S)
133” WB - SuperCab/5.5’ Bed - Trim 12” off the inlet pipe #26336S (do not use #26206S)
145” WB - SuperCrew/5.5’ Bed - Use inlet pipe #26336S with no modifications. (do not use #26206S)
145” WB - Regular Cab/8’ Bed - Use inlet pipe #26336S with no modifications. (do not use #26206S)
145” WB - SuperCab /6.5’ Bed - Use inlet pipe #26336S with no modifications. (do not use #26206S)
157” WB - SuperCrew /6.5’ Bed - Trim 6” off the extension pipe #26206S and use with inlet pipe #26336S.
163” WB - SuperCab /8’ Bed- Use inlet pipe #26336S and extension pipe #26206S with no modifications.

3) Place the inlet pipe onto the back of the existing OEM head pipe and fasten using the 3/8” nuts, bolts and washers provided in the hardware kit. Tighten just enough to hold in place, but still allow for adjustment.

4) Slide the inlet hanger #411HA over the back of the inlet pipe and insert the hanger into the factory rubber mount. Do not tighten this clamp yet.

Note: *Reg Cab/6.5’ Bed: This hanger is not used. *Super Cab/6.5’ Bed, Super Cab/8.0’ Bed and Super Crew – The rubber mount is bolted to the side of the frame, and must be relocated forward to the cross brace where you will find another factory mounting hole location.

5) Slide a 3” clamp #MC300BS onto the inlet neck of the muffler #853057-Z. Then place muffler onto the inlet pipe and support with a stand. Tighten the clamp just enough to hold in position, while still allowing for adjustment.

6) Slide a 3” clamp onto the muffler outlet neck. Place tailpipe #26224S into position over the axle and insert the hanger at the front and rear of the pipe into the rubber mounts on the vehicle and slide into the muffler outlet. Tighten the clamp just enough to hold, while still allowing for adjustment.

7) Place the stainless tip #ST429 onto the end of the tailpipe and adjust to the desired location. Then tighten the tip enough to hold, but still allow for adjustment.

8) Adjust the position of all the pipes and muffler to provide a satisfactory fit. A minimum of 3/4” clearance around all parts of the system must be maintained; while keeping suspension travel and vibration in mind. After adjustments have been made, securely tighten all clamps and install the 2 7/16” hanger keepers onto the hanger rods.

9) For a more secure installation, we recommend welding all slip-fit connections.