Cleaned up chamber a little, still right at 3.90" bore size. From the factory these heads are already bigger than the 273 bore.
Some people call the recess next to plug a depth point for the machine process...others say it's for the flame colonel. Food for thought..
Flowed after the chamber shape valve unshrouding, nothing else.note this head has a valve job , very basic, thin seat margin though lacking somewhat to the factory valve job top cut/lower.
Int cfm @28" 4" bore 1.78 valve
.100-59
.200-113
.300-165
.400-182
.500-178
.550-181
.600-181.5
.650-184
