The Cherry Bomb brand and glasspack-style mufflers have been around for decades, and they continue to be popular. They deliver a great sound and good performance at a decent price. Installing one is not difficult, if you know your way around power tools and vehicles. It is not recommended for the average shade tree mechanic, but for those who have experience beyond tune-ups and flat tire changes, it can save quite a few dollars to install the muffler at home.
Remove the old muffler. This step will require you to cut the exhaust tubing at either end of the existing muffler if the unit was welded in place. If the muffler was clamped on, many times the clamps can be removed using a large socket wrench. However, if the bolts have sized due to heat and moisture or if they are bent, it may still be necessary to cut either the bolts or the exhaust tubing itself.
Measure out how much room the new muffler will need between the remaining exhaust tubing. Generally, glasspacks are longer than standard mufflers and therefore will require more room. If more space is needed, it will be necessary to cut the exhaust tubing on one or both ends to accommodate the new unit. Cut carefully; if too much tubing is removed, the muffler will not install correctly. Take out only as much as you need, whether you are welding the new unit in or clamping it on.
Install the glasspack. If you are welding the new muffler in, be sure to get a 100-percent bead all the way around each end so there are no exhaust leaks in the system. Place the muffler carefully between the front and rear tubing and tack it so that it is suspended and check your tolerances. Once the muffler is correctly in place, complete the full weld. Always wear welding safety equipment and make sure the vehicle is sitting on jack stands if it is necessary to elevate it. If you are clamping the muffler on, always use new units. They can be found cheaply at any auto supply store and will last several times longer than the old clamps. Similar to the welding method, the muffler will be placed between the front and rear tubing, but simply clamped into place. Get the clamps as tight as you can to avoid failure or exhaust leaks.
Some mufflers only flow one way; pay attention to arrows on the unit.
Never work on a hot exhaust. Allow the vehicle to cool before modifications are made.