I see displacement more as a powerband selecter, your gonna use a powerband range of rpms about 2500 to 3000 rpms from stall to shift points in a drag race. The 434 powerband probaby will operate about 300 rpm less then 408 which is about 400-600 less than a 360. Which depends on what's done to the heads you might make peak hp mid/high 4000 rpms so Eg.. a 2500-5000 to 2800 - 5300 rpm stall to shift.