w2 rockers ratio

friend of mine called me last week end
and we were speaking roller rockers for
his w2 race heads he have and discussion
was going around he told me to have the correct
lift for w2 heads you need to get like 1.6 ratio
instead of 1.5 like OE heads

is it true ???

if so mine are 1.6 so was thinking
I hade more lift that use to

thanks bob