You need to define your goals a little more. An engine producing 400 HP has much different needs and components than one making 600 HP. Aluminum rods require a lot more attention and different engine building procedures than steel rods do, and aluminum rods are often not required or needed in anything other than just all out extreme HP and RPM situations where steel rods cannot survive. Aluminum rods also have a life expectancy, and since you can't tell by looking at them how many passes or time has been put on them, buying them or using them used is a big risk. Having assembled many aluminum rod race engines, they wouldn't necessarily be my first choice unless the engine requirements wouldn't let steel rods be the first choice.
