318 build using 302 heads

I always thought that the issue of a 2.02 valve in a 318 block had to do with the valve being shrouded by the cylinder wall when it was open, resulting in less flow than the 1.88 valve and that's why nobody used 2.02s with a 318 block - they could flow great as a head on a bench, but not on an actual motor. That's why it was suggested that the edge of the bore be notched at the top to provide clearance for flow.