Batten W2 Alloy Heads

To be direct here, the .100 to .400 lift numbers on those battens are weak.
So you need to lift the valve a lot more to put the mid lift where the head flows the most/more=.500 to .700

Ported j heads flow better in the .100 to .400 by an average 10cfm

every 5 cfm=10 hp theoretically

Those heads need an aggressive solid roller around.680 lift [to be as streetable as possible yet make some use of the head flow]

too bad they flow so good at sky high lifts meanwhile flowing stock'ish from .100-.400