Aftermarket mandrel-bent universal dual exhaust kits are a great source for parts when you need to build a full custom exhaust for your 4x4. These kits are available from a variety of exhaust companies and aftermarket parts suppliers. You can get them in diameters ranging from 2 inches all the way up to 3 1/2, and since they are universal they are designed to include enough pipe for very long cars and trucks from the 1970s. That means on a shorter, smaller 4x4, or on cars where you are only running single exhaust, or an after-cat system, the kit can yield enough bits to build a few exhausts. This kit is from Summit Racing Equipment. It’s a steal at $219.97 for a large amount of 2 1/2-inch aluminized steel. We have used this to build almost two complete 4x4 exhausts (with the addition of a few mufflers) and still have parts left over. These kits are also available in raw steel, aluminized steel, chrome, and stainless steel.