I'm with ED on this, there's nothing that increases the flow better than angle milling the heads.
Work with ED and Curtis on this build and i'm certain you'll have the baddest 540 on the planet. I have total respect for both of these builders and they know what they are doing.
In fact i'm going to talk serious to Curtis about doing my heads for my 383 blown motor, it's already been 4.62 @ 2600lbs when it was a 358" motor. Next i'm going to talk to my Doctor to see if i have the B?lls to drive it in an 1800lb Anglia.
Good luck and i think you made a wise choice to get new pistons. I can only hope that i helped in this decision with the formulia that i posted.
Zip.