The Brodix 18's do not flow 350 out of the box, suppose it depends on whos flow bench. All would have to be done on the same bench.
My Dart 18's flowed
330/260 @ .700 lift out of the box. My TEA ported LS1 heads flow
317/255 at only .600 lift. That is as much or more then my $4000 Dart 18 degree heads, with a factory $200 set of heads and $1200 worthe of valves and porting!
LS6 heads with porting
346/270 @ only .600 lift on a cheapy factory head!!
YOU CANNOT BEAT THAT WITH A STICK!