unless you have huge compression larger valves are a no-no on 273's.. use small valve 340-360 heads..no 2.02's!..car will really wake up and no notch needed..
And 273's don't have a lot going for them already. 360 heads with their large open combustion chamber will make what compression there is disappear. Send the stock heads out for a little porting and call it a day.
