Thats the chart I used gary, it work out .028 min at the top, .017 2nd conpress ring min, so I called KB they said go .030 on the top and .019 on the 2nd ring, just in case it gets to hot. they said .038 would be the max top ring gap. .030 over 454= 4.280 X 0.0065=0.02782 or .028 for the top and .004x4.280= 0.01712 or 0.017 for 2nd ring.