Seriously fella, if you can churn out 500 Watts plus for 5 minutes and you weight 65kg then you should be world class pro cyclist. Chris Boardman averaged around 7.86 W/kg for a little over 4 minutes during his world record pursuit - your 500W for 5 minutes would be 7.69W/kg.
I sense a big fat helping of forum bullsh@t here
Might it be that you can churn out 500 Watts for more like a minute? That'd put you on a par with many a 2nd/3rd/4th Cat racer.
urmm stf up mate , but yes i think i was kinda wrong i didnt realise how steep 10% is i thought this hill was 10% but its like 6% ,