What piston alloy do most of you go with? I'm building a 355 LT1 for a road race car, sustained 3.5k-7k rpms for a couple hours at a time. From my research the 2618 is more forgiving in regards to detonation, but this motor will maybe make 400 at the wheels, stock heads (worked by AI), stock intake, and I plan on making the tune stupid safe. I dont need every last drop of hp, longevity is key here. I have an 8 hour and 13 hour enduro race I want to do. So, 2618 or 4032? These are what I'm looking at, they are 4032-
https://m.summitracing.com/parts/dms-8705-4030

 

4032. More durable material for long-term use. Less expansion = tighter cold clearances.
No questions about it for your stated use.