Sometimes a quick fix is necessary to complete a project. A friend’s LS engine swap required cutting the exhaust lead-down pipes from the welded exhaust system in order to fit the new lead-down pipe to the new engine. After we cut the exhaust pipe on the driver’s side with a Sawz-All to realign the pipes, we now faced a new problem: How to join the two pipes together quickly.

This is our Walker butt joint band clamp positioned over the two exhaust pipes. This photo was taken after about 500 miles of driving with the clamp still in place with still no audible exhaust leaks. A trip to the exhaust shop for some welding is still in the plans. 

We did not have access to a welder, so we used a simple Walker 2½-inch butt joint clamp. Exhaust pipe is measured and spec’d by its outside diameters. The clamp we chose will work to join 2½-inch pipes of the same size. There are also lap-joint clamps designed to join two pipes together where the smaller pipe is slipped inside the larger one. We’ve listed both style clamps in the accompanying chart.

We pulled the pipes together as close as we could and used the band clamp to bring them together. We really didn’t expect the clamp to seal the exhaust, but we thought we could at least create an 80 percent connection that would allow us to drive the Chevelle to a muffler shop to have the two pipes permanently welded together. Amazingly, that telltale ticking exhaust leak that we expected never materialized.

great for joining pipes of different sizes such as a 3-inch connecting to a 2 ½-inch exhaust pipe.

Some may be tempted to turn this into something we like to call “Temporary Repairs That Become Permanent.” But because we’re using a pair of oxygen sensors located only slightly upstream of this connection, it’s best to do the job correctly and weld this connection together to ensure the O2 sensors will return accurate measurements.