Resto-Mod builders have many choices when it comes to headers, exhaust pipes, mufflers, tailpipes, resonators and tips. There are different brands and designs, pipes made of different materials, different finishes, different installation methods (slip fit or welded for instance) and different price ranges.
The least expensive option for a Resto-Mod builder is a stock exhaust like this Waldron's system for 455-powered 1971 Olds Cutlass and 4-4-2 models.
The least expensive option is probably the "stock look" exhaust system, which works on muscle cars with their original engines and chassis. Although the stock look exhaust system follows the OEM's (original equipment manufacturer's) design, it could be made of stainless steel instead of mild steel and it could have less restrictive mufflers or be put together by welding, rather than slip fit joints.
A custom modified "hot rod" exhaust system is the Resto-Mod builder's other choice. This is the route you'll have to take if your car has a crate engine or a custom frame. In fact, if your using a ready-to-roll bolt-in frame like the ones that Schwartz Performance builds and you go with their power train package, the engine will come with a specific exhaust system made for the frame you chose.
Even though the term "stock look seems self explanatory, there are at least four variations of this type of system according to muscle car collectors, dealers and parts suppliers. All of them are high-quality exhaust systems, but the best one for you to purchase depends on your own personal restoration goals.
There are concours style stock systems like this one that Mid America Motorworks offers for Corvettes with outside exhausts.
Mid America Motorworks also sells the OEM-style slotted covers for the factory style Corvette "off road" external exhausts.
There are concours style stock-look systems that are supposedly bent from the same pattern cards that original equipment suppliers used back in the '60s and '70s. These exhausts are usually sold only as complete systems and they are made for collectors who want their cars to be judged perfect originals. There is no reason, other than one-upmanship, to use these on Resto-Mods.
Secondly, there are stock-look systems bent from aftermarket pattern cards. These can be very close to factory perfect, but sometimes have manufacturing variances, such as indentations caused when the bending machine stretches the metal tubing. Also, many such systems use modern mufflers that are eyeball-matched to originals, but may not be identical.
Thirdly, there are reproduction stock look exhaust system components patterned off one part that fits multiple models. These fit and generally look OEM but they may have small differences. For instance, in a hypothetical case, an OEM Ford muffler might have looked like a Mercury muffler, but had a different part number. Today, the same reproduction part might be sold for both cars. Such parts may truly be "stock-looking," but might cost concours judging points.
Last, there are systems that are manufactured to OEM designs, but made of different materials like stainless steel. These pipes can be exact copies of factory parts, but stainless steel will virtually last forever. The stock look exhaust system made of stainless steel is probably the best options for the Resto-Mod builder who has only a mildly changed car and wants to keep exhaust costs low.
Exhaust systems aid the smooth flow of spent gases out of an engine and reduce noise. There are three ways to muffle engine sounds: restriction, reflection and absorption. Restriction means the flow of exhaust gas is restricted. This makes for a really quiet exhaust, but chokes off engine power. Most factory exhaust systems use restriction to keep cars quiet for the average motorist.
Hooker was one of the pioneer makers of performance exhausts, but today makes this system for the Chevy LS1 V-8 that Resto-Mod builders love.
Exhaust gas reflection involves splitting the flow path of the exhaust gases within the muffler and using wave-cancellation techniques to help create a pressure drop that reduces sound pressure and, therefore, reduces the noise level at the muffler's outlet. Reflective-type mufflers use a series of baffles and reflectors that the exhaust gases wind around in order to set up wave reflection.