If i add a new cat to my 77 the exhaust will not have odors. True or False

 

deleted: I didn't like my answer

 

If your exhaust is "Stinky". Perhaps your running rich?
often car's with carburetors will smell rich on cold start as with a choke plate they do tend to run a bit extra rich.
They may need that when it's 30 below. Maybe not so much when it's 45 above. But carburetors are not very smart.
I remember back in the 70's. Car's with Cats were stinkyer than those without. A different kind of smell. And definitely worse. I lost the cat on my 77 many, many years ago. I do not feel my exhaust is stinky.
When I ran a Holley carb it defiantly had that hot-rod smell on start up. But cleared when the choke came off. Was never overly happy with the electric choke.
Went EFI. No more hot-rod smell. It does know the difference between 30 below and 50 above. And no Cat.

 

I remember when the catalytic converters hit the roads of America. I was a motorcycle Courier inside Washington DC and you could identify every car with a catalytic converter by the Sulfuric smell they emitted. It was a bad time in the Automotive industry and every car had low compression and a catalytic converter.

Today's catalytic converters are more robust and they don't have that distinctive smell of rotten eggs. The newer materials are better at heating up and actually burning all the excess gasses from the combustion process. Today's cars have higher compression and no longer have issues with the smells despite the amazing performance that today's vehicles are capable of.

I would stick with the Factory Carburetor to keep the engine running as lean as it needs to. Then with a catalytic converter your emissions will be much more acceptable. I still have the catalytic converters on my C4 and have no intention of ever removing them. I replaced the factory unit with an oversize aftermarket catalytic converter from Summit and the car runs better than ever and still meets the emissions requirements.

Yes, 4-vettes is correct about the swap to an EFI system from a carburetor. It gets rid of many original carburetor related issues and makes the car more reliable. If I had a 1977 C3 with a federally mandated exhaust system (INSIDE the United States) then I would keep the catalytic whether or not the engine has EFI or a carburetor. It is a definite improvement with the modern components on the older engine. They actually look for the catalytic's when the car is getting it's annual safety inspection and this item could stop you from getting passed the inspection process. They even have infrared thermometers to see IF the catalytic is still working or not. I would leave an empty shell of a catalytic there just so they can see it.

My C3 with its 427 never made that much of a "Hot Rod" smell because I had the carburetor set up properly so it didn't run rich or even smell rich. With an off the shelf carburetor that was never properly setup you will have the "Hot Rod" smell as you referred to. The people at A.E.D. set my carburetor up before shipping it to me and I didn't have to change a thing except the idle screws. My A.E.D. carburetor has no choke tower so that is irrelevant. They had that carburetor working on a flow bench when they set it up. The owner of A.E.D. suggested that if it was not perfect that they would bring me to their shop and dyno my engine there to get it perfect. Then he wanted to take me and my C3 down to the Virginia International Raceway and see just how a L88 equipped Corvette would do with one of their custom carburetors on that racetrack.

I have had a Air/Fuel ratio gauge in my C3 for the past 10 years or so, it REALLY helps setting up a carburetor. With a gauge you see the live action of your carburetor working. With EFI you can see just how accurate the system is. With the prices so low on the air/fuel gauges I wouldn't try and set up a carburetor without one. If I didn't have a gauge I still know how to read spark plugs and know how to repair carburetors.

Newer tools make old mechanics faster.

 

False.