Trick Flow small block heads

I ported a set of Chevy Dart Platnum heads for a good Friend and the he bought a set of cnc’d 220 Chevy AFR heads. We flow tested them and they were nowhere near their advertised flow numbers. I did a lot of porting on those heads to get them right and her ended up running 10.40’s on a stock stroke 350 in his street strip S10 truck.
Just curious if this was in recent years and if they had the swirl/wing design?, also if they did if you get rid of it. Interesting since the ones I have been around have been excellent out of the box and a couple were tested on different benches. The main thing is out of all the sets I've seen only a few were flow tested but all the ones at the track ran the numbers they should for the power. Chevys being like rabbits their are no shortage of afr heads around here lol.