Flowmaster OUTLAW 817689 Service manual

409S Stainless Steel
08/29/17
Removal:
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) Support the muffler with a stand. Using a hacksaw or sawsall, cut the
stock tailpipe off just behind the muffler. Separate the wire hangers on the
tailpipe from the rubber mounts on the vehicle and remove the tailpipe from
the vehicle. This step is not mandatory but makes removal easier.
3) Using a 15mm wrench, loosen the bolt on the clamped ball connection
behind the catalytic converter. Separate the wire hangers from the rubber
mounts on the vehicle and lower the inlet pipe and muffler from the vehicle. A
lubricant will make removal much easier. You will need to remove the ball
clamp from the stock system; it will be reused with the Flowmaster system.
Installation:
1) Place inlet pipe assembly #26429S into position onto the ball
connection behind the catalytic converter. Reinstall the clamp onto the ball
connection and tighten enough to hold, but still allow for a small amount of
adjustment. Connect the hanger on the pipe to the rubber mount on the
vehicle.
2) If installing the system on a Crew Cab truck with a 6.5’ bed, place
extension pipe #TB700S onto the back of the #26429S inlet pipe, place a
provided clamp onto the slip-fit and tighten enough to hold in position. This
extension pipe will not be used on Double Cab or Crew Cab-5.5’ bed models.
Pg 1 of 4 Technical Support [phone]
Installation Instructions for:
SYSTEM #817689
2014-2018 GM SILVERADO/SIERRA 1500 · (NON HD)
FITS: 5.3L ENGINES ONLY
CREW CAB 4WD & DOUBLE CAB 2WD/4WD

3) Place a supplied 3” clamp over the inlet of the muffler, then slide the
inlet of muffler onto the back of the inlet pipe. Use a stand to support the
muffler. Tighten the clamp just enough to hold in position.
4) Slide rubber hanger #HA168 onto the end of 226HA, then using the
supplied bolts, washers, nuts and backing plates #HA566, mount the
assembly to the frame on the left side of the vehicle using the angled oblong
hole on the frame rail. Note: the backing plates #HA566 go on both sides of
the frame between the hanger, washers & bolts to cover the oblong holes so
that the frame hangers won’t bend into the oblong holes.
5) Place two of the supplied 3” clamps over the right and left outlets of
the muffler. Place right tailpipe #26431S into position over the rear axle, and
slide into the right muffler outlet. Connect the two hangers on the pipe to the
rubber mounts on the vehicle. Pipe should be approximately 3/4” away from
the shock when adjusted.
6) Place left front tailpipe section #26430S into position over the rear axle
and slide into the left muffler outlet. Place a supplied 3” clamp onto the back
of the pipe. Place left rear tailpipe section #26432S onto the front section,
and connect the hanger welded to the rear of the pipe into the rubber hanger
installed in step 3 above. Pipe should be centered between the shock and the
spare tire when adjusted. Tighten the clamps just enough to hold in position.
7) Slide the side exit pipes #26433S or the rear exit pipes #26434S onto
the ends of both over axle pipes and place a supplied 2-1/2” clamp onto these
slip-fit connections. Tighten just enough to hold in position. Place the two
stainless tips #ST462B onto the exit pipes and tighten them enough to hold
position. Rotate the exit pipes and tips to the desired distance from the body
or bumper, so that the angle cut on the tips are in the desired location.
8) Adjust the position of all pipes and muffler to provide a satisfactory fit. A minimum 3/4”
clearance around all parts of the system must be maintained; while also keeping suspension travel
and vibration in mind.
9) Tighten all clamped connections down securely. Place the supplied 1/2” hanger keepers onto
the end of the inlet pipe and tailpipe hangers. Slide the 7/16” hanger keeper onto the left rear frame
hanger up to the rubber mounts, to firmly hold the system in place.
10) To prevent the rear axle breather tube from contacting the left side tailpipe, and possibly being
damaged, use the enclosed zip tie to fasten the breather tube to the brake line bracket located on the
rear end. Be sure to allow hose enough slack for the suspension to fully compress and extend.
Pg 2 of 4 Technical Support [phone]

11) For a more secure installation, we highly recommend welding all slip-fit connections.
PACKING LIST
Qty Description Part #
1 Inlet Pipe 26429S
1 6.5’ Bed Extension TB700S
1 Muffler 8430155-Z
1 Tailpipe, Right 26431S
1 Tailpipe, Left Front 26430S
1 Tailpipe, Left Rear 26432S
2 Side Exit pipes R/L 26433S
2 Rear Exit Pipes R/L 26434S
2 Stainless Tips ST462B
1 Parts Kit PK770
1 Frame Hanger, Left 226HA
2 Backing Plate HA566
1 Rubber Hanger HA168
7 3" Clamp MC300BS
1 3/8" X 1-1/4” Bolts HW209
1 3/8" Nuts HW103
1 3/8" Flat Washers HW303
1 3/8" Lock Washers HW309
1 7/16" Hanger Keepers HW502
5 1/2" Hanger Keepers HW503
1 15” Zip Tie HW505
Pg 3 of 4 Technical Support [phone]

Technical Su
pp
ort
(
707
)
544-4761
Installation diagram for:
SYSTEM #817689
2014-2018 GM SILVERADO/SIERRA 1500 · (NON HD)
FITS: 5.3L ENGINES ONLY
CREW CAB 4WD & DOUBLE CAB 2WD/4WD
409S ® Stainless Steel