You will need at least 35 amp but for continuous full throttle use it would be safer to go with a 40 amp unit. The Kysosho will live long on 7 or 8 cell battery packs. Thought I read somewhere on Ezone where the max amperage measured was 37 amps. Mine flew fine with the 50 amp cheapo ($49) ESC from Great Planes (Tower Hobbies). Perhaps some of the electric experts can chime in on their recommendations.

By the way, the Sanyo RC2400 packs are the recommended battery type. Stay away from the NiMH packs and Panasonics due to their higher internal resistance. You will need a battery with little internal resistance that will give the Kyosho fan unit all the energy it needs. Expect the battery to be quite warm after running so a cool down of up to 30 minutes will be required before you recharge then another cool down cycle after the charge. All in all you are looking at considerable time between flights if you only have one battery pack. You will need a good charger and plenty of the RC2400's to have continuous fun.

The 600mah 8 cell pack you have will be good for about a minute to minute and a half of full throttle use so you want something in the 2400mah or more if you can handle the extra weight.

Good Luck!