I'd like to get to 160 to 165 trap speeds, but may be limited to how much HP a stock block will withstand? With these Victor heads, compression approaching 15 to 1, my 447 inch motor ran 154 MPH at sea level tracks. We race primarily in Denver, but also travel to Division 5 and 7 events, and encounter DAs ranging from 600 to 9500. We make adjustments for varying DAs by changing timing, jets, squirters, and moving ballast. Calculators show almost 800 HP to achieve the speeds we want.