74 power wagon dream truck...

I think I have some geometry issues with my Duster clutch. Something about when it starts getting really hot it won't want to go into first gear or go into reverse..
I doubt you have a geometry issue, that sounds more like a cheap parts store rebuilt clutch issue.
Replace it with a quality clutch/pressure plate and I bet the issue goes away.
I have had great luck with the Ram muscle car series clutch kits.