Bruce, The Q220 puts out 12,000 BTU, that is a size 60 orifice drill bit, I used a 3/64 drill bit to make it 15,000 BTU and I hit 700 degrees on a hot day,
If you want to hit 500 degrees I would say a size 57 or 58. I used a hand drill, and I also opened up the air inlet to the max,