Exhaust

[wopony12]

Has anyone installed headers and true dual exhaust on a 1987 Avanti. If so, what brand of headers and what mufflers and pipes are used.

Also, is there any problem with removing the catalytic converter and leaving off.

Thanks

[Gunslinger]

As far as the catalytic converter goes, it depends on your state laws. If your car qualifies as "historic" or "antique" or even "street rod" status, you can generally do away with the cat...again...depending on state law. If you have regular registration it gets more dicey when it comes to doing such things. Some states won't allow anything other than what's original or original equipment replacement.

For the rest of your exhaust, my own experience is that Sanderson Headers are top quality. For mufflers, a lot depends on what kind of sound you prefer...quiet...noisy? I like Magnaflow...they give a nice low burble that opens up with speed. Flowmaster makes a nice muffler but they're loud and raspy in comparison to Magnaflow. There's other brands as well...it just depends on which sounds best to your ears. A good speed or exhaust shop can fabricate the rest of your exhaust system.

[wopony12]

_{Thank you for your reply. In Ohio there is no emission testing for a vehicle over 25 yrs. old. My main concern is I will cause no damage to engine}

_{or performance by removing the catalytic converter. I believe the car does have a computer.}

_{I like your red convertible.}

_{Thanks again.}

[Gunslinger]

I'm guessing your car has either the computer-controlled carburetor or maybe TPI fuel injection since you have an on-board computer. If so, whomever installs your exhaust may have to install an 02 sensor to allow the computer to make adjustments. Not a big deal but the car probably won't run properly without the sensor.

[wopony12]

Thanks Gunslinger, you've been a big help. I just got to line up a set of headers that fit without a lot of mods.

[wopony12]

I do have a carburetor.

[IndyJimW]

The chassis is from a 87 Monte Carlo, headers for that will work. Get an aftermarket transmission crossmember with dual cutouts to run dual exhaust. You'll need a O2 sensor for the carburetor controls.

For more info go to Montecarloss.com website, they offer plenty of good ideas.

Jim Wood

[wopony12]

^{Thanks, information very helpful.}

[wopony12]

IndyJimW,

I enjoyed the pictures of your car. Is there any reason you have only one cat. Am I doing right thing to put headers and true dual exhaust with no cat. Thanks for your opinion.

[IndyJimW]

This is what the OEM & 1987 Avanti exhaust looks like, tailpipe ends are different on the 1987 Avanti.

The exhaust pipes bolt to the front of the convertor. My convertor was plugged when I purchased the car so I replaced it.

http://www.summitracing.com/parts/flo-2010035/overview/

I then installed a Cat-Back duel exhaust system. Those rear pipes connected at the convertor unlike the OEM system. So the convertor acts like a X-pipe. I had to modify the rear pipes to exit the Avanti.

If you want to run true duel exhaust you will need an aftermarket transmission support because there is no opening for exhaust on the left side of the support.

http://www.summitracing.com/parts/sum-770302/overview/

Good luck,

Jim Wood