John
This subject depends on how much you want too pay for better flow ?
I have one off those all singing and dancing heads and I think it's an improvement over stock !
Full boost by 4300 rpm (what ever it's set too could be 1.2 and sometimes 1.8bar
Power on my setup doesn't drop even at...
put it this way a 1.4mm zep gasket has 6.6cc my flat top pistons have deeper and wider pockets (custom) and at tdc 2.7 cc with my head cc aswell it makes 9.3/1 cr
with regards to bearings toyota all cross each other in size so more care is needed by machine shop for clearance and oil pressure...