What you‘ve seen is totally correct. We have strict requirements here...every 2 Years you have to make a „government tech check“ called Hauptuntersuchung. Also the classic ones...Everything! would be checked...rust holes, lights, bushings , emissions, belts, modifications, brakes, tires a.s.o...and you (hopefully) get the approval sticker for the next 2 yrs. on your license plate...if something is bad, you have to fix it in 4 weeks an show up again or pay a fine if they pull you over. When your involved in a crash without a valid sticker you‘re f****d 😒
If I swap in a 350/350 team i would approve it by the government. That will be okay, because the 350 was available for the Malibu in 79 with the TH350(The fact it’s not a wagon would be taken)Even, as said, no one will notice the swap, if something happens i don‘t want to loose my house or go to jail...