This is what I come up with on mortec
oval..CLOSED..396, 427, 98cc chamber
I had a simialr head on my 468 but with the stock 206 valves, obviously someone has cut the seats on your heads to the bigger 2.19 trouble is unless the vavles pockets were unshrouded and bowlhogged the bigger vavles wont make much difference.
These haeds worked great for me with the smaller cumbustion chamber it helped bump my compression up with a small domed pistons, they were all torque, pulling hard from idle to where I was shifting @ 5500
Goodluck Charles