Classic Mustang Small Block Dual Exhaust Install

Classic Mustang Small Block Dual Exhaust Install

Last Updated January 17, 2024 | Kevin Brent

The distinct roar of a Classic Mustang's exhaust is one of its most recognizable elements. For many Classic Mustang enthusiasts, a loud and powerful exhaust note is a primary selling point. Unfortunately, the exhaust system is one of the most vulnerable parts of the car when it comes to corrosion damage. If you're looking for a great way to refresh the look of your Classic Mustang's exhaust while improving power and sound, consider swapping out your 1965-1970 Mustang's stock exhaust for an aftermarket small block dual exhaust system.

Check out our step-by-step instructions below for a comprehensive Classic Mustang dual exhaust installation guide. With a few simple tools and a couple of hours, you'll be back on the road with new exhaust sound for your Classic Mustang.

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Tools Needed:

  • Ratchet & Socket Set with Extensions
  • Wrenches
  • Air Impact Wrench
  • Air Ratchet
  • Reciprocating Saw
  • 1/2" Side Cutter
  • Large Screwdriver/Pry Bar
  • Light Gauge Wire

1965-1970 Mustang Small Block Dual Exhaust Install

We chose a 1964-1970 Mustang dual exhaust kit for this installation. This kit fits small block Ford engines, which refers to 260/289 and 302 engine designs. Installation will be similar for most Classic Mustang exhaust systems, just make sure you have an exhaust system that fits your year and model. Most kits also include all the necessary hardware to upgrade your exhaust.

Step 1: Raise the Mustang and Lubricate the Exhaust

Use a jack to raise your Mustang. Place jack stands under the front frame rails so that you can work underneath the car on a tarp or carpet. Spray penetrating oil on all of the exhaust clamps beneath your Mustang.

Raised Classic Mustang exhaust

Step 2: Remove Exhaust System Nuts

Remove each of the exhaust studs using a 5/8 inch wrench or socket. If the nuts are rusted, apply more penetrating fluid and wait several hours, then try again.

Removing Classic Mustang exhaust bolts

Step 3: Remove Exhaust Clamps

Remove each of the 1/2 inch exhaust clamp nuts with an impact wrench. Once they are removed, set the clamps aside.

Removing Classic Mustang exhaust clamps

Step 4: Disconnect Weld Points

Disconnect your stock exhaust pipes at each weld point. The rear joint ahead of the Mustang rear axle on our model was both welded and clamped.

If that's the case in your old exhaust, just cut the pipe ahead of the weld to free the Mustang Y-pipe and mid-pipe.

Disconnecting Classic Mustang exhaust weld points

Step 5: Cut Welded Exhaust Hanger

Cut the welded hanger on the driver side of the muffler. Be careful to stay clear of the Mustang fuel tank. Use the reciprocating saw and cut toward the front, away from the fuel tank.

Cutting Classic Mustang exhaust hanger

Step 6: Remove Muffler Exhaust Hanger

Remove the Mustang exhaust clamp on the passenger side hanger and lower the muffler to the ground.

Removing Classic Mustang muffler hanger

Step 7: Remove Stock Muffler

With the clamps removed, secure the muffler with your hands and work it side to side rotating the muffler so it is free from the frame. Make sure you clear the axle, fuel tank and springs.

Removing Classic Mustang stock muffler

Step 8: Remove Stock Exhaust Pipes

Carefully remove the rest of the exhaust pipes. Be sure to watch the axle, fuel tank, and springs.

Removing Classic Mustang stock exhaust pipes

Step 9: Install Exhaust Manifold Flanges

Raise the new exhaust system so it sits roughly in the factory position. Start with the front pipes and work to the rear.

Place the supplied doughnut adapters on the H-pipe and install the supplied flanges on the left and right exhaust manifolds.

Installing Classic Mustang exhaust manifold flanges

Step 10: Position the H-Pipe

Use light gauge wire to tie the back of the Mustang H-pipe to the frame. This will hold it in place while you reinstall the hangers.

Positioning an H-pipe on a Classic Mustang

Step 11: Position the Mid-Pipes

Tie back the mid-pipes and space them evenly from side to side and along the drive shaft. Place the supplied exhaust clamps at each of the joints and tighten them slightly.

Positioning an mid-pipe on a Classic Mustang

Step 12: Position the Muffler

Install the new muffler with the inlets at the front and the outlets centered at the rear. Add the supplied clamps and tighten them slightly.

Positioning a muffler beneath a Classic Mustang

Step 13: Support the Muffler with Light Gauge Wire

Use light gauge wire to hold the muffler in position as you install and clamp up the new tailpipe.

Adding support to a Classic Mustang muffler

Step 14: Install New Hangers

Place the hangers on the frame rail at the OEM hanger locations.

Installing new exhaust hangers on a Classic Mustang

Step 15: Install Tailpipe clamps

Clamp the tailpipes to the corresponding locations on the muffler and hanger. Rotate and center the pipes between the springs and the fuel tank.

Clamping a tailpipe to the muffler of a Classic Mustang

Step 16: Adjust Exhaust Position and Tighten Clamps

Step back and look at the balance and angle of all the pipes on your new Mustang exhaust. Move and adjust the components to provide adequate clearance and symmetry. Then, tighten all the clamps. Don't forget to reinstall the manifold nuts.

Adjusting the exhaust positioning on a Classic Mustang

Step 17: Add Exhaust Tips

Check again for clearance, then install the Mustang exhaust tips over the tailpipes.

Upgrade the Rest of Your Classic Mustang's Exhaust System

Installing a new dual exhaust on your Classic Mustang helps overhaul a rusted stock system while giving you a custom sound. You'll enjoy performance gains with a system that will last you much longer than the stock option.

If you're looking for more ways to upgrade your classic Mustang's exhaust, we offer a wide variety of options. From aftermarket exhaust pipes to mufflers to hardware, check out the button below to shop our selection of Classic Mustang exhaust parts.

This article was researched, written, edited, and reviewed following the steps outlined in our editorial process. Learn more about CJ's editorial standards and guidelines.