I am thinking more of the overall strength of the engine. The 225 was rated at what 145 horse. It was designed and built with a strong enough bottom end to support that. I am surprised that any added power enhancements can live with the4 main block. Like I said, it must have a strong crankshaft. I am surprised Ma Mopar didn't build any 6 cylinders any bigger than the 225. That is undersized compare to the GM 230, 250, and 292 and the Fords 240,250, and 300 all which were 7 main engines. I come from John Deere country and none of their gas or diesel's would live any length of time if they were 4 main engines. Just not strong enough.