Well, first - I couldn’t find evidence - but I’d assume it’s the same belt since…ever…so you’re looking for a belt with the profile
HTD 8M
a length of
1440
mm and a width of
13
mm.
Just mix that up and you get
HTD 1440 8M 13
you should be able to find cheap ones via ebay or maybe local.
Still not cheap enough?
If you do not mind a really ugly color I could send you a steel-cored free sample belt.
Regarding question two:
Yes, the identical part numbers ST-435 at the parts drawing front and rear do indicate that 