BMW S65 Engine, overbore and stroke to 4.6L?

The S65 engine in the E9X M3 was once the most powerful naturally aspirated V8 engine of its time. While the E9X M3 is still highly praised for its exceptional handling, its factory output of 420HP seems modest compared to the turbocharged engines of newer German models. Additionally, the Alusil block of the S65 tends to lose power over time, with an E92 M3 at 100,000 miles potentially having only around 290 WHP remaining.

As a result, many E92 M3 owners are now looking to extract more power from their engines. Among the various options, the stroker and overbore kits are the most sought after. In this video, we will discuss the issues associated with some stroker kits, especially when the goal is simply to swap the crankshaft and internals without further modifications.