Loud noises after I had the head gasket replaced on 2002 Buick Century

I had my head gaskets replaced a couple months ago. Ever since I feel like the car just sounds louder. I don't remember ever really being able to hear the engine when I would accelerate but now I can.

After I got the gaskets replaced it was still a little cold out so I turned the heat on, drove for about an hour and a half straight with no problems. A few hours later I went all the way back home and ran to the store. When I got in my car and started it the heat was already set to on and it sounded REALLY loud, it was kind of like a whirry and buzzy noise I guess would be the best way to describe it. Ever since it only does it sometimes. It's the same thing with the A/C. Could this have anything to do with having my head gaskets replaced? Do you think these two problems are related?

Asked by for the 2002 Buick Century
the blower motor is a separate system. that is one noise. the other noise is a exhaust leak. take it back to the shop and have them properly seal the exhaust.