The aftermarket weather-stripping just sucks honestly.
My 81 Cutlass with semi dry-rotted factory seals seals great. No wind noise, no leaks. I am NOT a body guy and was able to get the window to seal pretty darn well with minimal effort. Doors close easy and windows roll up no problem.
My 86 GP was missing window seals when I bought it and I put new ones in. I am unable to get them to get them to seal where I don't get wind noise, doesn't leak in rain, or rolls up when the door is closed. I have spent hours trying to get it to seal and can't. Have to slam the door to close and the window won't roll up all the way unless I open the door.
The stock seals are coated in a smooth almost plastic covering that allows the window to slide easily, aftermarket seals are just smooth rubber and stick.
Stock seals are soft foam, aftermarket are harder rubber.
The aftermarket seals on the top roof rail are C shaped where factory are more stair stepped and I can't pull the window height limits up enough to sit in the channel without the window hitting the bottom of the channel. I have to pull the window down like 3/16" from the channel for it to clear the seal when I close the door.
The B pillar portion is too stiff and it forces the window out, and the A pillar portion isn't fluffy enough to seal on the window.
NOS GM seals or a good set from a salvage yard are really the only good option.