How to Install 1963-1973 Corvette Mufflers

For many Corvette owners, the sweet song of a Chevy V8 is a cherished part of the soundtrack of our lives. But the exhaust system is a wearing component, or more accurately a corroding component, of our cars. 

Fortunately, Corvette Central manufactures their exhaust systems so you can count on USA-made proven quality at a very reasonable price. And we offer many options for various applications and tastes. Two videos can aid in your choice and they are at the end of this article. One presents the sound from old stock Corvette mufflers.  The second video is after the installation of new N11 off-road Corvette mufflers. 

Installing 1963-1973 Corvette Mufflers

Let’s look at the choices for C2 and C3 Corvettes when it’s time to replace the mufflers. Then we’ll show muffler replacement with some installation tips. Yes, sometimes it can be exhausting work (sorry) but the reward is music to your ears.

The following mufflers are available from Corvette Central:

Available C2 Corvette Mufflers:

• 322361  63-67 2″ Mufflers
• 322362  63-67 2-1/2″ Mufflers
• 322319  63-67 2″ Magnaflow Mufflers
• 322080  63-67 2-1/2″ Magnaflow Mufflers
• 322349  63-67 2-1/2″ Off Road Mufflers – Clamp On
• 322419  63 2″ OEM Style Welded Mufflers
• 322425  64-67 2″ OEM Style Welded Mufflers
• 322363  63 2-1/2″ OEM Style Welded Mufflers
• 322634  64-67 2-1/2″ OEM Style Welded Mufflers
• 322104  64-67 2-1/2″ Off Road Welded Mufflers

Available C3 Corvette Mufflers: 

• 323371  68-72 2″ Mufflers
• 323372  68-72 2-1/2″ Mufflers
• 323380  73 2″ Mufflers
• 323381  73 2-1/2″ Mufflers
• 323112  68-72 2″ Magnaflow Mufflers
• 323416  68-72 2-1/2″ Magnaflow Mufflers
• 323505  68-72 2″ OEM Style Welded Mufflers – 4 Speed
• 323514  68-72 2-1/2″ Auto OEM Style Welded Mufflers
• 323564  68-72 2-1/2″ 4-Speed OEM Style Welded Mufflers
• 323571  73 2″ Automatic OEM Style Welded Mufflers
• 323524  73 2″ 4 Speed OEM Style Welded Mufflers
• 323549  73 2-1/2″ SB Automatic OEM Style Mufflers
• 323501  73 2-1/2″ OEM Style Welded Mufflers
• 323325  68-72 2-1/2″ Off Road Mufflers Clamp On 
• 323025  68-72 2-1/2″ 4 Spd N11 Off Road Welded Mufflers
• 323102  68-72 2-1/2″ Auto N11 Off Road Welded Mufflers

How To Install Mufflers On a 63-73 Corvette: A Step-By-Step Guide

01. Determine whether you want separate mufflers or a welded pair. 

In a welded pair of Corvette mufflers, the muffler is welded to the intermediate pipe, as it was from the factory. For originality and judging choose the welded pair as shown here (68-72 MUFFLER 2 1/2″ 4 SPEED OEM STYLE WELDED, #323564). However, after 50 years of use, it’s common for Corvettes to have the replacement clamp-on mufflers and that opens up more options, including many separate muffler selections. 

Corvette Central offers original-style Aluminized mufflers that have five baffles. They are the least loud but still sound healthy and are a good choice for drivers who want to avoid the exhaust droning when cruising.  

Magnaflow mufflers shown here are another option. They have a Stainless Steel case but look close to stock and are a little louder. The pipe goes straight through the muffler with no chambers, baffles, or louvers so if you want the least resistance to exhaust flow Magnaflow is a good choice.

For the purposes of this step-by-step guide to installing mufflers on a 63-73 Corvette, we are installing the factory optional off-road 68-72 N11 mufflers (Clamp-On). These were developed by Corvette Central to replicate the sound of the original N11 muffler. Like the originals, they have only three baffles and are the loudest. These N11s are aluminized so they’ll look good for years — if not decades.

02. Make sure you have all the materials you need. 

Beyond the mufflers themselves, there are 

a few extra parts and pieces you might need for this muffler installation project. 

Exhaust Clamps. Corvette Central offers multiple choices for the exhaust clamps. Heavy-duty clamps (3/8-16 with 9/16 nuts) are available in both steel and stainless steel. If guillotine clamps are your preference, they are also available in both steel and stainless steel. Tip: If you are ordering clamps for the exhaust extensions, be aware they may be 2” even if the exhaust pipes are 2-½”.

Hanger Kit. It’s a good idea to order a hanger kit too (63 322176, 64-67 #322187, 68-72 #323289, 73 #323290). The rubber gets tired or stretched after years of heat and strain. The kits include all needed bolts, nuts, and washers.

New exhaust donuts and sleeves. These are a good idea to have handy if you are removing the front pipes at the same time. It is not uncommon for the sleeves to have been left out in previous work and they aid sealing at the exhaust manifold.

03. Check your muffler outlet pipe. 

Some Corvette models feature an offset muffler outlet pipe. For example, the muffler outlet pipe is offset where it goes into 70-72 Corvette exhaust extensions. For 1973, the pipe was centered. Because 73 mufflers were one-year-only, there are fewer options for this year. 

Tip: Switch to 70-72 mufflers and extensions on your 73; you’ll have a wider choice of mufflers and only an NCRS judge will notice the difference.

04. Gather Your Tools

Here are some of the items that can make installing your 1963-73 Corvette muffler a little easier. 

• Rubber hammer for removing and installing the exhaust extensions. 
• Penetrating oil for clamps, bolts and for the pipe itself. 
• Heavy gloves to protect your hands when twisting and wrestling with the muffler. 
• And a Dremel tool with cutoff discs if the muffler resists coming off.

05. Remove the exhaust extension first

When possible, remove the exhaust extension first. It’s easier to pull and twist the extension while the muffler is bolted solidly to the exhaust pipe. 

06. Remove the two bolts that attach the hanger to the muffler. 

Then remove the nut and bolt that attaches the hanger to the frame. Insert a 9/16 wrench through the wide slot in the frame to keep the bolt from turning. With the hanger and extension out of the way, it’s easier to twist the muffler back and forth to remove it.

07. Remove the original muffler.

Here’s a tip for removing the original muffler on your 1963-73 Corvette: use a jack to hold the intermediate pipe firmly up against the strut rod bracket. That makes it easier to wiggle and twist the muffler off the pipe. Don’t worry if the exhaust pipe is somewhat flattened where it goes under the strut rod bracket – that’s normal.

If the muffler is too tight on the pipe, use a Dremel tool with a cutoff disc to cut through the muffler pipe. When available, using an air impact hammer with a chisel bit or heating it with an oxy-acetylene torch is even faster. Twist the muffler back and forth until it comes off. Heavy gloves can help protect your hands from getting smashed.

08. Install the extension after the new muffler is installed and clamped to the exhaust pipe. 

Once the new muffler is installed and clamped to the exhaust pipe, it’s time to install the extension.  A rubber hammer can help tap it into the desired position. Once in place and aligned, tighten the clamp. I generally place the nuts up but on some years the nuts face toward the center of the car if originality is a concern.

The slots in both ends of these hangers enable a lot of adjustment to help position the exhaust extension up and down and left to right.

09. Tighten nuts and bolts. 

When you’re satisfied with the alignment and position of the exhaust extension, tighten all the nuts and bolts down securely, and then enjoy the sweet music of the big V8. 

10. Enjoy your newly installed 1963-73 Corvette muffler!

It is impressive how long aluminized exhaust mufflers and pipes last. After decades of use, this muffler still is solid and looks good. However, well over 100,000 miles of use and abuse caused a baffle to finally come loose and rattle. This proved to be a good excuse to install the more aggressive sounding N11 mufflers.

Story and photos courtesy John Pfanstiehl

 

Stock exhaust sounds on a C3 Corvette

Exhaust sounds on a C3 Corvette with Corvette Central’s Off-Road N11 Welded Mufflers