One Relay or Two

I'm installing a dual fan assembly from a 2001 Dodge Intrepid that originally used 2 relays. One for hi speed & one for low speed. My question is, can't I use one relay and one circuit breaker for both fans in one speed only? I've included a wiring schematic for reference. I'm wondering if they will provide enough cooling for a 414" stroker with well over 400hp with a Champion 26" radiator. I have no idea how much CFM they flow. Any comments, suggestions, feedback?