Different starters pull a range of current to start the engine on hot days and cold days. If you have a clamp-on ammeter, simply put it around a battery cable and turn the engine over; you will read the actual amps required. It'll probably be around 500-800A.
Good Answer - Its probably closer tot he 800 this time of year. The real question is, "what are you trying to do with this information?"
I only get good cranking power with the RG25XC battery (Astro)