So you guys are telling me that if I put an aftermarket pair of cats on they'll burn off the excess co2?
Do cats add alot of exhaust restriction?
Do they quiet the system like a muffler would?
There were literally thousands of cars built before catalytic converters were mandatory... all with carburetors.... and you may be suprised to know that none of them stunk like you are saying your car does... I know, I'm old and have lived through the time of cars with no cats.
A car with a proper tune, with carb set correctly and not burning oil will NOT have an overpoweringly nasty exhaust smell.... it's going to have an exhaust smell, but not one that will make your clothes stink if you've driven with the windows down.
A buddy of mine had an '85 Mustang 5.0 with the same problem you're explaining and if I'd follow him down the road, my eyes would actually tear up the smell of unburnt fuel was so bad. So we swapped cars and he followed me while I was in his car so he could experience how bad it was... then I followed him while he was in my car and there was no smell at all coming from mine. He leaned out the carb and the problem went away... and neither of our cars have cats.
Installing cats on your car isn't going to make the bad smell go away, it may actually make it worse becasue the cats give off a "rotten egg" smell... and combined with whatever your REAL problem is, it's going to make for one crappy smelling exhaust.
Plain and simple, it is not normal for a car to have a foul exhaust smell... you need to figure out if you're running too rich or if your car is need of a tune or tune up, or if you have an oil consumption problem with the rings or valve stem seals.