I am thinking of replacing / adjusting the window felts. My doors seem rattley when I close the door when the windows are in the down position.

Are you sure its the felts and not a busted window motor bracket? You'll have to get the door panel off to check this.

Sounds to me like the small rectangular anti-rattle pads that mount on the  inside of the window to keep it firm in the slot.

The door panels have to come off, but that should be a combo of screws at various places (I'm stalling as I can't remember them all) including behind the door handle inside.  3 up inside the arm rest, one at the small piece end and 2 under the main pad.  One at the front of the door on top and possibly one at the bottom on the back.

There is some factory GM goo that holds the sound deadener/wind block paper or plastic to the door, but it will come off if you pull the bottom out and then lift up over the sill at the top.  It will come easy, so if it is difficult, you have not pulled everything.  If you have manual windows, there will be a clip behind the center part that must come off (DON'T LOSE THIS).  You can get a puller at autozone in the help section, or any smallish hook tool you have will pull it off.

It is a keeper clip, open at one end, that recesses into the handle to grab a recess on the window roller head.  Pull straight back to you once you find it.  Medium pressure is all you should need.

Finally, with the panel off, you will find the anti-rattle pads (or not) at the sill, bolted in from the passenger side.   I doubt you will get these from a local parts store, but you can find them at most Vette supply houses.

If you need more detail, I'll be happy to take some pix.  If you have a shop manual, it shows them but you need to study it a bit to get the feel of where the go and how to adjust them for best fit.

I'll be out all day, but will check back to see tonight if you need anything more or you can PM me.

Good Luck!

Bernie, replacing the window door seals is a good move. The following is what I did on my 75, not sure a 80 like yours is the same but here goes. The ones on the outside are in the door itself, and the ones inside are part of the door panel. Outsides are easy to remove with a screw driver.  Held in position with a button fastener and  pop right back in.  They really eliminate the movement of the door glass in the down position and flopping around in the down. Also really help in guiding the window up. The felt atti-rattle pads help guide the glass up and down and assist the window door seals. The door panel does need to be removed to replace these pads. Ajust them in the down position then roll the window up and recheck and ajust.  Hope this helps thanks.

OK thanks for the responses. I have electric windows and they go up and down good it just doesn't sound solid when I close the door with the windows in the down position. I saw a door with the panel off but wasn't sure how to access the felt piece. I have not pulled the door panel off yet but seems like I will need to to get to these and evaluate what needs adjustment or replacement. I figured it was best to check in before starting this project since there may be some tricks or tips. I will go ahead and pull off the door panel and see what I have going on. Is there anything else I should lubricate or adjust once I have the door panel off (as long as it is not too hard of a job)?

Guy is right.  Check the window felt (long strip) and rubber sweep to see if they are in tact or need replacement.  I would use some white lithium grease in the window tracks and on the gear teeth . It also wouldn't hurt to lube the latch mechanism.

'Lectric winders that "rattle" when you close the door most likely have the winder motor support bracket broken. This allows the hole thing to bounce when you close the door. They do make replacement brackets, usually in stainless steel, to prevent the bracket from breaking again.
Take a look at this pic...in the lower, center area, to the left of the winder motor, you'll see a part that goes directly to the door. It's kinda rectangular, with a couple of creases in it, and silver metal. That is the bracket that breaks. The replacements bolt on. hth

                                                  Click for linkAdams' Apple2008-03-05 21:08:48

You need the assembly instruction manual (AIM) for your year.  AIM will show how the doors and hardware were put together and will be very helpful if you dive in there. 6880Mike2008-02-04 06:26:21

Thanks for the responses. I was hoping to have some time today to check it out but had an unexpected home crisis that took the whole day to fix. At least I got to go on a nice ride tonight. I love this car......... Hopefully next weekend.