I don't know of anyone who has ever put the clark 5 speed in a G506. It won't fit without major rework.... if you could readily put the 5 speed clark on the 235 I'm sure I would have heard about it.
COE's were never produced in large qty for either the G506 or G508... their non-standard parts made things difficult for supply.
I do have a G506 and G508 COE manual... but your best bet is to hit ebay for a digital manual.
