I have a '82 380SL with a 1986 560 engine and transmission and it is a big difference in power. I did not do the exchange though. It was like that when I bought it. I did have to solve an idle problem, as it would not idle down below 1200 rpms. We changed the air contol unit on the front of the engine to one for a 380 and it now idles at 600 rpms. Runs great and now the only problem is the price of gasoline.