These motors are used in fast electric 1/8 scale hydroplanes and can handle 8S, if you want to go that high:
i. NEU 1527 1.5Y 850KV
ii. HET Typhoon 700-98 840KV
iii. Turnigy SK3-3994 850KV
iv. TP 4040 10Y 830KV
You were asking about the KV rating, these are all between 830 and 850KV