440 Source Head Opinions?

Why would they sell stroker kits and then have stock flowing cylinder heads? They should have an option for a high flowing cylinder head as well
http://store.440source.com/Cylinder-Heads-Components/departments/1/
Cylinder Heads & Components-440 Source
http://store.440source.com/Cylinder-Heads-Components/departments/1/
As you wish kind sir.