Heads question

hi, the 1.88 valve head will provide more than enough air flow to run low 12 secs. i have seen, putting 2.02 valves in j heads, loose port velocity. in the mid lift area, the 1.88 will out flow the 2.02, this is where the valve spends 90% of it's time, opening or closing. .100 to .400 lift. a 340 or a 360 stocker can run low 11 secs with this head and valve size.