Not sure why you can't find window felt as it is in the store link at the upper portion of the forum..
Here is all the weatherstripping. If you don't see what you need, email me
http://store.73-87chevytrucks.com/merchant2/merchant.mvc?Screen=CTGY&Store_Code=7&Category_Code=WTHR
It is easier to swap to a newer door than use the 73-early 74 ones...
The glass track can be removed from the glass. As far as I know the 73 version is available...
Thanks for the link
The first time I searched the store i didn't see the pre 80
Anyhow
I swapped the handle shafts yesterday
Not difficult
Passenger side.:
Remove the regulator
Crank the regulator to the down position
Put a C clamp on the toothed rack so it wont fly when you remove the crank
(I've seen people get their teeth knocked out when it lets loose )
Drill out the rivets and remove the cranker
I found some bolts that had a really thin head
You will need one to replace the rivet under the rack
With the cranker removed You will need to pull the rack past the cranker to access that hole.
Plug the screw in that hole then release the rack back to the C clamp
Put small bolts in the other two holes.
Drop the cranker on the bolts and tighten the nuts
Done
Also when we pull our regulators out of one door we discovered that the regulator and glass was a 74+ model. With the large rollers on the glass and the large roller for the door roller track was replaced with a bolt and several jam nuts sandwiching a properly sized steel washer in place of the plastic roller
To replace the rivets under the rack You can also use a small screw for a countersunk hole and lightly countersink the hole in the regulator
For the drivers side you can crank the rack around enough to access all three holes
Don't forget he C clamps
There's a lot of energy stored up in the spring
Also don't mess with the cranker gear assembly
They have a coil spring inside that has to fit a certain way