904....or 998 / 999?

Hi Guys,

these are both non lock up transmissions, no machined input shaft.....

I´d just like to know if there´s anything "special" to these transmissions. What about these ribs in the case? is this for sure a indication to say it´s a 998 or 999?

Any measurements i can do to make sure i get the right clutches?

Is there a way to check the first gear ratio? I´d like to know the ingredients when i put them together.

Thanks for Info!

Michael