A crate 5.9l makes 400 hp @ 5400 rpms which at that rpm is displacing about 563 cfm of air a 318 would need to turn just over 6100 rpm to displace about the same amount of air aka both engines would be the same size at those rpms. So you would need a cam the would peak around 6000-6300 rpm for the 318 doesn't necessarily mean need a different cam or even if you do, doesn't mean need more duration to do so maybe different opening and closing points and or LSA could need a little more lift and or duration but I wouldn't imagine all that much. The 3 magazine 400 hp 318 do it with different cams from xe268h, xe275h, 280h so 224-231.
