Pardon me for my ignorance. I just obtained a 1977 450SL with a brand new top, straight body, and a rusted out engine. (my first mercedes)

I'm looking to replace the engine but I'm having a hard time finding one. I did come across a 1976 450SL engine however.

My question is: Will the 1976 engine work for my 1977? All I know the cat is in a differnt location.

Thanks,
blueone