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New C4 Exhaust System - More Bark With Your Bite, Part 2 - Tech

Our Project '87 Gets A New Set Of Vocal Cords

Dick Moritz Sep 29, 2008
Corp_0810_01_z 1987_corvete_upgraded_exhaust_system Exhaust_system 2/36

Picking up where we left off last month, we removed the heat shield on the passenger side to allow for installation of the right-side header. This shield keeps exhaust heat away from fuel lines and filters. It required a little cutting after the header was installed in order to allow a sufficient air gap between the header and the shield.

You'll remember in Part 1, we removed the stock exhaust system from our '87 in preparation for an upgraded exhaust system that includes a gorgeous set of headers from Stainless Works, a high-performance catalytic converter from Random Technology, and a cat-back system from Corsa.

Removing the old system was no big deal. the only casualties were a couple of broken exhaust manifold studs, which we'll leave to whoever decides to restore this car 25 years from now. installing the left-side header was pretty straightforward as well, with a couple of minor complications such as having to make up a new rear alternator support bracket and stud, and accommodating a too-close-for-comfort fit between the header and the oil line that runs from the oil filter housing forward to the engine block.

Corp_0810_02_z 1987_corvete_upgraded_exhaust_system Manifold_nuts 3/36

Two of the three manifold nuts were so heavily rusted that the studs broke off, even though we had sprayed them liberally with penetrant. if we were going to re-use these manifolds, we would have replaced the studs and also used extra-long brass nuts made specifically for use on exhaust manifold studs.

This time we'll install the right-side header and the rest of the system. as you'll see, installing this header presented some interesting challenges that required a healthy dose of creativity and patience. In fact, we give high marks to the folks at Stainless Works for designing a header that fits where few other headers would dare to tread. It's just that the passenger side of the engine compartment was designed to accommodate assembly-line parts, and the original exhaust manifold was integrated into the design. Aftermarket suppliers, on the other hand, have to work within the space available and be inventive enough to design headers that breathe properly, while providing as much clearance as possible with other parts and systems.

the job was, at times, difficult and challenging, but worth the effort. The result is an exhaust system that has just the right sound and just the right look-subtle, yet serious-while affording ground clearance and decibel ratings that are just fine for a daily driver without being obnoxious. we also expect the benefits will extend to our next trip down the quarter-mile. We'll keep you posted.

Corp_0810_03_z 1987_corvete_upgraded_exhaust_system Underside_car 4/36

We marked the underside of the car at the rear edge of the catalytic converter flange. This allowed us to be sure the new system was in the proper fore-and-aft position to ensure proper alignment and positioning. Here, barely visible, is the hose clamp that holds the A.I.R. tube in place on the passenger side as seen from below. We're not sure when this clamp might have been installed when the car was built, but there's surely no way to get any kind of screwdriver on it or even a 1/4-inch drive socket, so we used a small box wrench to loosen it.

Parts List
Stainless Works
C48591 '85-'91 Corvette headers plus
NBC250 (4) accuseal high torque band clamp
EBC250 (2) accuseal wide high torque band clamp

Random Technology
191-30001 high-performance catalytic converter w/accy's

Mid America Motorworks
628-096 Corsa exhaust system cat-back
603-930 catalytic converter hose kit
614-559 (2) muffler insulators

Local speed shop
ARP header bolt kit
Header gasket set
Local Chevy dealer
Dipstick tube

Tools Of The Trade
In addition to everyday hand tools, such as screwdrivers, wrenches, and sockets, you'll also need:5/16-inch, 12-point, 1/4-inch drive socket for header bolts
1/4-inch open end or box wrench for hose clamps for A.I.R. hose
Torx T-20 socket
Cut-off wheel
Improvised spark plug wrench


Random Technology
Loganville, GA 30052
Stainless Works
Chargrin Falls, OH 44023
Mid America Motorworks
Effingham, IL
Classic Coatings
Sheboygan, WI



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