does anyone know what the differences are between W5 head and these so far they seem to be much more raised port hence the need for the intake spacer in the valley and the intake bolt pattern is std A .......what is the exhaust pattern and location ? W5 ? W5 being higher than W2 ? would W5 rockers work also ? maybe easier than the Victor big block ? I have W5's and would look at these as an up grade