Any install a catalytic converter on a 1st gen? I'm asking, because I've got a strong fuel/exhaust smell that has always been with this motor, before and after rebuilt, and after several exhaust mods to see if I could get the smell to vent differently. I've checked for leaks, and havent found any. Also, It did this with 2 different carbs, and the EZ EFI system I currently have. So, I'm curious if anyone has put a catalytic converter on a 1st gen, and if so how...seems pretty tight. Thoughts on the idea?

That's not a "strong fuel/exhaust smell". That's a nostalgic aroma that triggers memories. The roar of the V8, "Born to Be Wild" or "Shut Down" playing and the smell of exhaust. ahhhhhhh

Sorry, don't know of anyone who has put on a catalytic converter.

I now a guy in Costa Rica who has cats on his bird (like once a year)....2 of them ,one for ea side...but no pictures ,and I`ve lost his email.....

but down there he needs them for inspection.....then removes them until next years inspection, so he has two pipes the same length as the cats , just bolts one on ,takes one off...so it does work...no idea on which cats he uses, but there are several kinds...I bought after an market skinny one for my old Volvo 780 a few years ago.

You would wipe that cat out just about as soon as you put it on the car. These motors run on average 2% to 3% CO and between 300 and 600 ppm's of HC's(unburned gas) and thats with a good tune on mostly stock motor. The BAR in Cali had maximums for these cars at 5.5% CO and 650 ppm's of HC if I remember correctly, been a long time since mine needed to be smogged. Cats are not made to handle that kind of exhaust emissions. Not to mention they are performance killers, especially when they start to get plugged.

I'm with Jim - I thought that exhaust that brings tears to your eyes and lingering odors to you clothes (if you run it too long in an enclosed space, even with the garage door open)was part of the appeal of a classic car

But more on the practical side (to add to Doc's comments), you also have to take into account the space issue for 2 cats, as most likely your performance car has dual exhaust.

FGF floorpans were not set up for cat converters.

I wouldn't want to miss my wife complaining about how I stunk up the house by running my car in the garage.

What kind of fuel are you running? Not all gas is created equal.... I noticed that my 428 running on CAM2 doesn't omit as much of an odor as 400 running on 94 octane with an additive from marathon. I put some 93 octane in the 400 and it did not like it at all it omitted a rancid odor. I've never had any quality tests run on octane ratings of different fuel companies but sure that the info should be available somewhere.

There's a thread on another forum regarding the fuel line hoses and HC smell. http://www.pro-touring.com/showthread.php?79183-Kicked-out-of-the-Garage!!-EZ-EFI-fuel-line-odors.&highlight=smell

Modern honeycomb catalysts are nothing like the old pellet style which severely robbed power and plugged easily (compounded by manufacturers trying to get away with feedback carburetors for closed loop operation).

You have the EZ-EFI system, which should keep your part throttle at stoich, therefore catalyst longevity should not be a problem. Granted it probably doesn't have the catalyst protection strategies that the latest OEM ECUs use, but it does have wide-band control to keep from running too lean at WOT. You should still easily be able to get 100k miles out of them.

A properly sized catalyst should have negligible effect on power. I had a '93 Z28 that a test pipe fabricated for track use. Testing on the same day, multiple runs with and without catalyst, showed no change in 1/4 mile or trap speed. The Corvette ZR1 makes 638hp through the catalysts. Be sure to consult with the manufacturer for the minimum suggested size and mounting length from the collector.

I've enjoyed the banter...yep, its the wife who doesn't like the smell. FirebirdMike, thanks for the info, I would love to see if it will work, but still not certain how I could get them to fit. I need to do some research on size to see what will fit.

Another thought: Are you sure your carburetor is OK? I see that you have tried two different carbs but maybe both were a bit off?

I had a very strong fuel/exhaust smell on my Firebird earlier (much more than normal for an old car), and it didn't go very well at idle and low speeds. I thought that the idle circuit was too rich, because of the exhaust smell at idle.
I then was told by a guy who is a carburetor specialist that the idle circuit was TOO LEAN. To make the engine idle at all, I had apparently turned the idle adjustment screw in so the throttle blades were opening too much, which made the carb run on the main circuit. Hence the over rich condition at idle.

It turned out that someone had tried to modify my carb and taken out a couple of small air bleed nozzles. By replacing these nozzles, I could adjust the carb back to get a strong and steady idle, and the exhaust smells are now normal for an old car.

Ronnie Stensson
Sweden

Dr. D's correct, raw fuel will burn out a cat cnvtr.

Don't forget, cats suffered through the 70's on carbed engines and survived quite well as long as they didn't get poisoned. Not much chance of that with unleaded being the only fuel around. Reasonable fuel mixtures are expected however.

The main issue for older carbed cars is that the NOx won't get addressed with the same efficiency as an EFI equipped engine.

I think for now I will will continue to investigate the option, although I don't know how I would fit them under the car, would need to be creative. The EZ EFI system helped with the smell, but wondering how much it could be reduced. Thanks

If you were using a transverse crossflow muffler, you could fit the cat where the resonator goes. Pretty sure a heat shield is still necessary, along with air space.