Help! Disaster or not here is the question

I bought a V8 at Ebay a few days ago (risky risky, I know it)...

And after I register it today, it's like I've been described elsewhere. serious stories..........

My question now is whether someone with V8 experience from Hamburg might risk an ear, an eye and a small test drive to help me decide whether there is anything else.......so in terms of engine sound and power development, he really only runs on 7 cylinders ect. - someone who knows how to feel better...

I would of course come by or to a meeting place to be determined, is clear

And something else....on Friday I will definitely change the transmission oil - maybe that's just it (although the really bumpy switches at the moment, and how)

the questions are...

Which transmission oil do I take there?

and how much? I think I have read that the measuring rod is often missing (I have to peek again...) - how do I measure the gear oil or where do I get a replacement measuring rod?

Hmmm - I'm going to use the forum search again, but maybe anyone else has good tips for me, I'm grateful for any help.

Greetings.
Alex (from Hamburg)