Doug, i a little bias but i like Brodix 18's, but almost everyone's 18 degree seem to flow about the same CC'ed, about 370 CFM. Brodix told me a couple yrs. ago with hand massaging it's possible to get around 395 CFM. There was also a head porter in Mo. that uss step down to 3/8" studs that claimed to get 430 CFM with the Brodix, Cost about $3500.00 complete.
I know you can make 850/900 HP with the 18* heads, perhaps a 100 HP more than 23* heads. You can also go bigger than a 1050 dom with them.
the car below is a local car and a friend of mine i've seen the car 5.18 in the 1/8 mi. which translates to mid to low 8's. But it has SB2.2 type heads on it. It weighs about 2300 lbs and is an all tube car. It also has a 1250 dom. on it.
I don't know how much HP he's making but it's a real hand full to drive.
JMO
Zip.
