A/C blows stronger than the heat on 99 Buick Century Limited

Hello.  My heat is hot and a/c cold.  All vents put out air. I changed the blower because
it was squealing.  I went in the engine compartment and changed the cabin air filter and
vacuumed the junk around it. It was filthy and I was excited. But still the A/C blows
stronger from all vents. If I have the electric temp set at 60 it blows strong. As I raise
the temp and it gets above 75, the air pressure becomes weaker, almost obstructed. I
dont know if there is an A/C door and a Heat door that open upon demand. Going
crazy, but I have heat (hot heat), just little pressure. Are they supposed to blow equally
storng???? Please help. Thanks