1976 Trans Am 400 auto California emissions low mileage. Engine has never been apart and carb has never been off. I want to rebuild carb. Car is stock other than exhaust changed to 2 1/2 dual exhaust, no converter, no egr. I do not know what jets are in it. Is there anything I can do to upgrade performance some by changing jet size? If so, what size jets should I order. When car was built emissions and fuel economy was a concern. Better performance is my concern. I do not want to take engine apart. Slightly better acceleration is fine.