the emissions coming from my car smells, when my mechanic hit the catalytic convertor, he didn't hear anything. Can it still be bad, if not, what could be wrong with it.

what is the mileage? had any coolant leak into the motor recently?

The mileage of the car is about 63,600. I have not noticed any coolant leak.

any other symptond like loss of power, exhaust color, noises from motor, loss of fluid?

Sometimes when i am pressing on the gas, it feels like it loses power for a couple seconds. In addition,for a 5.0 engine, i think it would a more power when going uphill.

is the mileage measured in kilometers or miles? is the original reading or has the odometer lapped once already, so is the reading 163,600 or 263,600 perhaps? the vehicles from 1980's burned oil, and some even required leaded gasoline, rather than unleaded gasoline. is the exhaust black in colour? which would account for the smell. loss of power on hill climbs usually an indicator of worn cams on the camshaft. and if it is carburated, then the carb probably needs to be adjusted and cleaned. hope this helps to pinpoint the issues, but there may be more based upon the age of the vehicle.

usually catalytic converter is replaced around 200,000 kilometers. the catalytic converter captures larger smog and emmissions particles so that these particles are not expelled into the atmosphere. an indicator of a full catalytic is absolutely reduced power, it is even difficult to get the vehicle in first gear. the check engine or service indicator will turn on, if the vehicle is equipped with these features. and a code reader will help to read the codes that have been sent from the computer in the vehicle.

If your Cats are plugged up, you will usually get a rotten egg smell. Most times anyways. Have your mechanic check out the flow performance on your exhaust system.