Most cam shaft suppliers can help with distributor drive gear.
The distributor shaft gear is available from several sources, including www.summitracing.com
All of the AMC V-8 engine parts for the cam drive, distributor drive, distributors, ect. will interchange.
Getting parts is not a problem, but is sometimes expensive...
(Haven't made them since 1990)
Here are a few things you should think about...
1. What caused the 'Stripped Out' gears?
The distributor shaft also turns the oil pump, did the oil pump lock up for some reason?
2. Is the 'Stripped Out' actually 'Stripped', or is it just AMC warn out?
Do you see broken, chipped or sheered teeth, or are they warn down into sharp edges? (Just worn out!)
3. Have you considered how you are going to get a steady supply of oil to the new distributor gear, fuel pump eccentric & timing chain so this doesn't happen again?
AMC engines are horrible about getting any oil to the front cam drive accessories.
There are a couple of ways of fixing the problem, both are cheap, but must be done when the front cover is off...
4. '75 has the Prestolite ignition in it.
If you are going to spend a lot of money on a distributor drive gear, you may be better off using a distributor out of a '78 or newer AMC V-8 (Motorcraft distributor version)
Cheap and easy upgrades, smog legal to do, and much more dependable.
Replacement parts are much cheaper also.
If you need specifics on any of this, and can't find it on search, PM me and we'll figure something out.