1968 Chevy Nova Exhaust System - Exhaustive Research

A Pair Of QTP Exhaust Cutouts Give This Bracket Nova 11 More Horsepower In Just Seconds At The Flick Of A Switch.

Frank H. Cicerale Jun 1, 2009 0 Comment(s)
Sucp_0906_26_z 1968_chevy_nova_exhaust_system Muffler_flange_cut 2/31

The mufflers were originally bolted to a flange on a collector extension. The kit called for relocating the mufflers to the stock position, so we had to cut the flanges off of the mufflers so we could reuse them.

As for the QTP cutouts, well that install was as easy as pie. It took us a little over four hours at W&W Auto and Truck Repair in Bound Brook, New Jersey, to get the job done, but that's only because we were extra careful in measuring, cutting, and welding. The cutouts fit along the first portion of the mid-pipe, with the electric solenoids that operate the cutout blades being hidden between the cutout itself and the inner portion of the subframe connector. The only gripe we had was we should have gotten a larger diameter cutout, as we had to open up the exhaust pipe opening to slip the cutout inside slightly. Without performing that task, we would have had to flush weld the cutout to the pipe, which would have been messy and nasty looking.

The wiring was also simple. Once the Weatherpak connectors were linked up, we had to drill a hole in the firewall and run the wires into the cabin of the car. After the toggle switch was mounted to the shifter pedestal, we ran the power lead to a key-on power source, cranked the big 406 Mouse up, and depressed the toggle switch. A few seconds later, we were rewarded with that open header cackle we all love so much, without having to go under the car and undo a few bolts to get it. Ah, the beauty of technology!

While track data wasn't available to gather since the install was performed in the middle of winter here in wonderful northeast, we were able to strap the Nova to the dyno to see just what it made with the new pipe on and the cutouts both open and closed. We cruised down to Crazy Horse Racing in South Amboy, NJ, where the car was tightened down to the rollers, fired up, and beat in anger. With the new exhaust on and the cutouts closed, the Nova cranked out 355 rear wheel horsepower. After a short cool down period, we depressed the toggle switch, allowing the solenoids to cycle the butterflies on the cutouts into the open position.

The muffled sound emanating from the tailpipes quickly changed to a nasty, angry cackle with a slight hint of NASCAR Cup car to it. The loud pedal was planted, the small-block screamed, and the open cutouts allowed the Nova to crank out 366 rear wheel horsepower, an 11 horsepower increase. We would have loved to compare the torque curves but a glitch in the dyno prevented us from doing that.

Either way, the little Chevy II made a noticeable increase in power with the cutouts open, with the air/fuel ratio remaining nearly the same both open and closed. The A/F ran between 12.1-12.3 closed, with a slight jump at 4,000 rpm to 12.5 when the cutouts were open. Other than that, the A/F ratio both open and closed were nearly identical. While the car could stand a jet change to lean it out and make some more power, we decided to leave things well enough alone and do a honest-to-goodness A to B comparison. Timing was set at a conservative 34 degrees.


Hooker Headers
Aberdeen, MS 39730
Crazy Horse Racing
South Amboy, NJ 08879
Quick Time Performance




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